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Vulnerability record · CVE-2026-8946 · published 19 May 2026

CVE-2026-8946: Mozilla firefox memory buffer overflow vulnerability

Mozilla · Firefox

Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

7.5 CVSS 3.1 High EPSS 0.60% · top 53.3% CWE-119 · Memory buffer overflowCWE-787 · Out-of-bounds write
7.5CVSS 3.1 base score
0.60%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
30References
15 Jul 2026Last modified by NVD

Description

Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.mozilla.org/show_bug.cgi?id=2029070 Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-46/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-47/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-48/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-51/ Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:21378
https://access.redhat.com/errata/RHSA-2026:21380
https://access.redhat.com/errata/RHSA-2026:21381
https://access.redhat.com/errata/RHSA-2026:21382
https://access.redhat.com/errata/RHSA-2026:22325
https://access.redhat.com/errata/RHSA-2026:22643
https://access.redhat.com/errata/RHSA-2026:26174
https://access.redhat.com/errata/RHSA-2026:26268
https://access.redhat.com/errata/RHSA-2026:26269
https://access.redhat.com/errata/RHSA-2026:26270
https://access.redhat.com/errata/RHSA-2026:26491
https://access.redhat.com/errata/RHSA-2026:26492
https://access.redhat.com/errata/RHSA-2026:26493
https://access.redhat.com/errata/RHSA-2026:26521
https://access.redhat.com/errata/RHSA-2026:26536
https://access.redhat.com/errata/RHSA-2026:26539
https://access.redhat.com/errata/RHSA-2026:26551
https://access.redhat.com/errata/RHSA-2026:26606
https://access.redhat.com/errata/RHSA-2026:26629
https://access.redhat.com/errata/RHSA-2026:26630
https://access.redhat.com/errata/RHSA-2026:27715
https://access.redhat.com/security/cve/CVE-2026-8946
https://bugzilla.redhat.com/show_bug.cgi?id=2479849
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8946.json

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-8946), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.