Vulnerability identifier: #VU52338

Vulnerability risk: Medium

CVSSv3.1: 6.2 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-23999

CWE-ID: CWE-277

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers

Vendor: Mozilla

Description

the vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to the way Firefox handles Blob URLs. If a Blob URL was loaded through some unusual user interaction, it could have been loaded by the System Principal and granted additional privileges that should not be granted to web content.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 87.0

Firefox ESR: 78.0 - 78.9.0, 68.0 - 68.12.0, 60.0 - 60.9.0

---

CPE

• cpe:2.3:a:mozilla:mozilla_firefox:87.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:86.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:86.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:85.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:85.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:85.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:84.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:84.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:84.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:83.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:82.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:82.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:82.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:82.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:81.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:81.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:81.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:80.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:80.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:79.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:78.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:78.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:78.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:77.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:77.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:76.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:76.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:75.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:74.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:74.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:73.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:73.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:72.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:72.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:72.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:71.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:70.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:70.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:69.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:69.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:69.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:69.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:68.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:68.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:68.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:67.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:67.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:67.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:67.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:67.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:66.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:66.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:66.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:66.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.6.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.6.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.5.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.5.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.4.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.2.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:66.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:66.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:65.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:63.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:63.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:65.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:64.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:64.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:65.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:64.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:63.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:62.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:62.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:62.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:62.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:61.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:61.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:61.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:mozilla_firefox:60.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.9.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.8.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.7.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.4.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.4.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.3.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:78.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.12.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.11.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.10.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.9.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.8.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.4.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.4.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.4.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.9.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:68.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.8.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.7.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.7.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.6.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.6.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.6.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.5.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.3.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.5.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.4.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.2.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox_esr:60.0:*:*:*:*:*:*:*

External links
http://www.mozilla.org/en-US/security/advisories/mfsa2021-16/
http://www.mozilla.org/en-US/security/advisories/mfsa2021-15/

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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