CVE-2026-0891
Memory safety bugs fixed in Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147
- State
- Published
- Severity
- 8.1 High
- Published
- Jan 13, 2026
- Updated
- Jul 15, 2026
- Reserved
- Jan 13, 2026
Description
Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.1 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H | CISA-ADP |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H | redhat-SADP |
Weaknesses
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
Affected Products
| Product | Versions |
|---|---|
FirefoxMozilla |
|
ThunderbirdMozilla |
|
References
- Memory safety bugs fixed in Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147
- https://www.mozilla.org/security/advisories/mfsa2026-01/
- https://www.mozilla.org/security/advisories/mfsa2026-03/
- https://www.mozilla.org/security/advisories/mfsa2026-04/
- https://www.mozilla.org/security/advisories/mfsa2026-05/
- https://access.redhat.com/security/cve/CVE-2026-0891vdb-entry
- RHBZ#2428963issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-0891.json
- https://access.redhat.com/errata/RHSA-2026:2231vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2271vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2286vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:0667vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2220vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2074vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1471vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2073vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1461vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2070vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1487vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2069vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1462vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2047vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1413vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2044vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1415vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2041vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1414vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:2043vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:1320vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:0694vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:0924vendor-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.