Multiple vulnerabilities in Mozilla Firefox and Firefox ESR



Published: 2020-11-17 | Updated: 2021-07-01
Risk High
Patch available YES
Number of vulnerabilities 17
CVE-ID CVE-2020-26951
CVE-2020-26952
CVE-2020-26959
CVE-2020-26958
CVE-2020-26956
CVE-2020-26953
CVE-2020-16012
CVE-2020-26960
CVE-2020-26961
CVE-2020-26962
CVE-2020-26963
CVE-2020-26965
CVE-2020-26966
CVE-2020-26967
CVE-2020-26968
CVE-2020-26969
CVE-2020-15999
CWE-ID CWE-20
CWE-119
CWE-416
CWE-264
CWE-79
CWE-346
CWE-358
CWE-435
CWE-399
CWE-200
CWE-122
Exploitation vector Network
Public exploit Public exploit code for vulnerability #7 is available.
Vulnerability #17 is being exploited in the wild.
Vulnerable software
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Mozilla Firefox
Client/Desktop applications / Web browsers

Firefox ESR
Client/Desktop applications / Web browsers

Vendor Mozilla

Security Bulletin

This security bulletin contains information about 17 vulnerabilities.

1) Input validation error

EUVDB-ID: #VU48458

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26951

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to insufficient validation of user-supplied input. A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass the built-in sanitizer.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Buffer overflow

EUVDB-ID: #VU48459

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26952

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing HTML content. The incorrect bookkeeping of functions inlined during JIT compilation when handling out-of-memory errors can trigger memory corruption and allow remote code execution.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 80.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Use-after-free

EUVDB-ID: #VU48464

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26959

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error within the WebRequestService component during browser shutdown. A remote attacker can create a specially crafted web page, trick the victim into visiting it, force the victim to shutdown the browser, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

4) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU48463

Risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26958

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due Firefox does not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker. A remote attacker can exploit this behavior to perform a cross-site script inclusion vulnerability or bypass implemented Content Security Policy restrictions.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

5) Universal cross-site scripting

EUVDB-ID: #VU48462

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26956

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data. In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

6) Insufficient UI Warning of Dangerous Operations

EUVDB-ID: #VU48461

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26953

CWE-ID: N/A

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to the way under certain conditions Firefox enters the fullscreen mode without displaying UI notification. A remote attacker can perform a phishing attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Firefox ESR: 60.0 - 78.4.1

Mozilla Firefox: 60.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

7) Origin validation error

EUVDB-ID: #VU48460

Risk: Medium

CVSSv3.1: 4.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-16012

CWE-ID: CWE-346 - Origin Validation Error

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to the way browser handles requests to cross-origin images. When drawing a transparent image on top of an unknown cross-origin image, the Skia library drawImage function takes a variable amount of time depending on the content of the underlying image. This results in cross-origin information exposure of image content through timing side-channel attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

8) Use-after-free

EUVDB-ID: #VU48465

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26960

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error within nsTArray implementation. If the Compact() method was called on an nsTArray, the array could have been reallocated without updating other pointers. A remote attacker can create a specially crafted web page, trick the victim into visiting it, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

9) Improperly implemented security check for standard

EUVDB-ID: #VU48466

Risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26961

CWE-ID: CWE-358 - Improperly Implemented Security Check for Standard

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a DNS rebinding attack.

The vulnerability exists due to the way Firefox filters IPv4 mapped IP addresses. When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver. However when an IPv4 address was mapped through IPv6, these addresses were erroneously let through, leading to a potential DNS Rebinding attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

10) Improper Interaction Between Multiple Correctly-Behaving Entities

EUVDB-ID: #VU48467

Risk: Low

CVSSv3.1: 2.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26962

CWE-ID: CWE-435 - Improper Interaction Between Multiple Correctly-Behaving Entities

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists in the way cross-origin iframes supported login autofill is being performed. Cross-origin iframes that contained a login form could have been recognized by the login autofill service and populated. This could have been used in clickjacking attacks, as well as be read across partitions in dynamic first party isolation.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 80.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

11) Resource management error

EUVDB-ID: #VU48468

Risk: Low

CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26963

CWE-ID: CWE-399 - Resource Management Errors

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper management of internal resources. Repeated calls to the history and location interfaces could have been used to hang the browser.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 80.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

12) Information disclosure

EUVDB-ID: #VU48469

Risk: Low

CVSSv3.1: 2.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26965

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a local user to gain access to potentially sensitive information.

The vulnerability exists due to the way software keyboards are handled by the Firefox. Some websites have a feature "Show Password" where clicking a button will change a password field into a textbook field, revealing the typed password. If, when using a software keyboard that remembers user input, a user typed their password and used that feature, the type of the password field was changed, resulting in a keyboard layout change and the possibility for the software keyboard to remember the typed password.

A local user leverage this behavior to gain access to passwords, stored by software keyboards.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

13) Information disclosure

EUVDB-ID: #VU48470

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26966

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to the way Firefox performs searches of single-word queries. Searching for a single word from the address bar cause an mDNS request to be sent on the local network searching for a hostname consisting of that string. A remote attacker with the local network can intercept the DNS query and obtain information, searched via browser address bar.

Note, the vulnerability affects Windows users only.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

14) Resource management error

EUVDB-ID: #VU48471

Risk: Low

CVSSv3.1: 3.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26967

CWE-ID: CWE-399 - Resource Management Errors

Exploit availability: No

Description

The vulnerability allows a remote attacker to introduce an unexpected behavior.

The vulnerability exists due to improper management of internal resources within Mutation Observers. When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 80.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

15) Buffer overflow

EUVDB-ID: #VU48472

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26968

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing HTML content. A remote attacker can create a specially crafted web page, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 78.4.1

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

16) Buffer overflow

EUVDB-ID: #VU48473

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26969

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing HTML content. A remote attacker can create a specially crafted web page, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 80.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

17) Heap-based buffer overflow

EUVDB-ID: #VU47741

Risk: Critical

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2020-15999

CWE-ID: CWE-122 - Heap-based Buffer Overflow

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in freetype library when processing TTF files. A remote attacker can pass specially crafted TTF file with PNG sbit glyphs to the application, trigger heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note, this vulnerability is being actively exploited in the wild.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Firefox ESR: 60.0 - 78.4.1

Mozilla Firefox: 60.0 - 82.0.3

External links

http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.



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