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Vulnerability record · CVE-2026-2791 · published 24 February 2026

CVE-2026-2791: Mozilla firefox authentication bypass via alternate path vulnerability

Mozilla · Firefox

Mitigation bypass in the Networking: Cache component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

9.8 CVSS 3.1 Critical EPSS 0.54% · top 57.0% CWE-288 · Authentication bypass via alternate path
9.8CVSS 3.1 base score
0.54%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
5References
17 Jun 2026Last modified by NVD

Description

Mitigation bypass in the Networking: Cache component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

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

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=2015220 Issue TrackingPermissions Required
https://www.mozilla.org/security/advisories/mfsa2026-13/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-15/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-16/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-17/ Vendor Advisory

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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-2026-2791), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.