What is CVE-2025-11719?

CVE-2025-11719 is a critical-severity vulnerability in Microsoft Windows, classified under Use After Free. CVSS score: 9.8/10. Published 2025-10-14.

How severe is CVE-2025-11719?

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

Use After Free in Microsoft Windows

CVE-2025-11719

Starting in Thunderbird 143, the use of the native messaging API by web extensions on Windows could lead to crashes caused by use-after-free memory corruption. This vulnerability was fixed in Firefox 144 and Thunderbird 144.

Vulnerability class: Use-After-Free

Published 2025-10-14 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.004 (26.7th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000

Affected products

Microsoft Windows
Mozilla Firefox — versions 144
Mozilla Thunderbird — versions 144

Weakness classification (CWE)

CWE-416 — Use After Free

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
www.mozilla.org/security/advisories/mfsa2025-81/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2025-84/ (Vendor Advisory)

Frequently asked questions

What is CVE-2025-11719?: CVE-2025-11719 is a critical-severity vulnerability in Microsoft Windows, classified under Use After Free. CVSS score: 9.8/10. Published 2025-10-14.
How severe is CVE-2025-11719?: Critical severity. CVSS v3 base score is 9.8 out of 10.