CVE-2023-6856
The WebGL `DrawElementsInstanced` method was susceptible to a heap buffer overflow when used on systems with the Mesa VM driver.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 20.6%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
Description
The WebGL `DrawElementsInstanced` method was susceptible to a heap buffer overflow when used on systems with the Mesa VM driver. This issue could allow an attacker to perform remote code execution and sandbox escape. This vulnerability affects Firefox ESR < 115.6, Thunderbird < 115.6, and Firefox < 121.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 20.63% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird · debian/debian linux
- Source
- security@mozilla.org
EPSS 20.6% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1843782Issue Tracking, Permissions Required
- https://lists.debian.org/debian-lts-announce/2023/12/msg00020.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/12/msg00021.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202401-10Third Party Advisory
- https://www.debian.org/security/2023/dsa-5581Third Party Advisory
- https://www.debian.org/security/2023/dsa-5582Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2023-54/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2023-55/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2023-56/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1843782Issue Tracking, Permissions Required
- https://lists.debian.org/debian-lts-announce/2023/12/msg00020.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/12/msg00021.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202401-10Third Party Advisory
- https://www.debian.org/security/2023/dsa-5581Third Party Advisory
- https://www.debian.org/security/2023/dsa-5582Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2023-54/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2023-55/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2023-56/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.