#VU56376 Buffer overflow in Firefox ESR - CVE-2021-38495

Vulnerability identifier: #VU56376

Vulnerability risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-38495

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mozilla

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

Firefox ESR: 91.0 - 91.0.1

---

External links
https://www.mozilla.org/en-US/security/advisories/mfsa2021-40/

---

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.