Vulnerability Description
Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
CVSS Score
8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 115.37.0 |
| Mozilla | Thunderbird | < 140.12.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2036929Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-57/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-58/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-59/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-60/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-61/Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:27717
- https://access.redhat.com/errata/RHSA-2026:27733
- https://access.redhat.com/errata/RHSA-2026:27734
- https://access.redhat.com/errata/RHSA-2026:29940
- https://access.redhat.com/errata/RHSA-2026:30846
- https://access.redhat.com/errata/RHSA-2026:33445
- https://access.redhat.com/errata/RHSA-2026:36100
- https://access.redhat.com/errata/RHSA-2026:36101
- https://access.redhat.com/errata/RHSA-2026:36102
FAQ
What is CVE-2026-12291?
CVE-2026-12291 is a vulnerability with a CVSS score of 8.8 (HIGH). Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
How severe is CVE-2026-12291?
CVE-2026-12291 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-12291?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.