Buffer overflow in Mozilla Firefox

CVE-2023-6856

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.

Vulnerability class: Buffer Overflow

EPSS: 0.205 (97.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-6856?
CVE-2023-6856 is a high-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2023-12-19.
How severe is CVE-2023-6856?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2023-6856 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.