What is CVE-2025-49709?

CVE-2025-49709 is a critical-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2025-06-11.

How severe is CVE-2025-49709?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Mozilla Firefox

CVE-2025-49709

Certain canvas operations could have lead to memory corruption. This vulnerability was fixed in Firefox 139.0.4.

Vulnerability class: Buffer Overflow

EPSS: 0.006 (43.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Mozilla Firefox — versions 139.0.4

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

security@mozilla.org (Permissions Required)
security@mozilla.org (Vendor Advisory)

Frequently asked questions

What is CVE-2025-49709?: CVE-2025-49709 is a critical-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2025-06-11.
How severe is CVE-2025-49709?: Critical severity. CVSS v3 base score is 9.8 out of 10.