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8.8

Firefox and Thunderbird: Heap Overflow in libvpx Could Crash Browser

CVE-2026-2447
Summary

Some versions of Firefox and Thunderbird are vulnerable to a bug that could cause the browser to crash or behave unexpectedly. This issue affects users of older versions of these browsers, making them more susceptible to crashes. Users should update to the latest version to resolve the issue.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software
VendorProductAffected versionsFix available
mozilla firefox <= 115.32.1
mozilla firefox <= 147.0.4
mozilla firefox > 116.0 , <= 140.7.1
mozilla thunderbird <= 140.7.2
mozilla thunderbird > 141.0 , <= 147.0.2
Original title
Heap buffer overflow in libvpx. This vulnerability affects Firefox < 147.0.4, Firefox ESR < 140.7.1, Firefox ESR < 115.32.1, Thunderbird < 140.7.2, and Thunderbird < 147.0.2.
Original description
Heap buffer overflow in libvpx. This vulnerability affects Firefox < 147.0.4, Firefox ESR < 140.7.1, Firefox ESR < 115.32.1, Thunderbird < 140.7.2, and Thunderbird < 147.0.2.
nvd CVSS3.1 8.8
Vulnerability type
CWE-122 Heap-based Buffer Overflow
Published: 16 Feb 2026 · Updated: 11 Mar 2026 · First seen: 6 Mar 2026