CVE-2026-0891

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.
References
Link Resource
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1964722%2C2000981%2C2003100%2C2003278 Broken Link
https://www.mozilla.org/security/advisories/mfsa2026-01/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-03/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-04/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-05/ Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:0667
https://access.redhat.com/errata/RHSA-2026:0694
https://access.redhat.com/errata/RHSA-2026:0924
https://access.redhat.com/errata/RHSA-2026:1320
https://access.redhat.com/errata/RHSA-2026:1413
https://access.redhat.com/errata/RHSA-2026:1414
https://access.redhat.com/errata/RHSA-2026:1415
https://access.redhat.com/errata/RHSA-2026:1461
https://access.redhat.com/errata/RHSA-2026:1462
https://access.redhat.com/errata/RHSA-2026:1471
https://access.redhat.com/errata/RHSA-2026:1487
https://access.redhat.com/errata/RHSA-2026:2041
https://access.redhat.com/errata/RHSA-2026:2043
https://access.redhat.com/errata/RHSA-2026:2044
https://access.redhat.com/errata/RHSA-2026:2047
https://access.redhat.com/errata/RHSA-2026:2069
https://access.redhat.com/errata/RHSA-2026:2070
https://access.redhat.com/errata/RHSA-2026:2073
https://access.redhat.com/errata/RHSA-2026:2074
https://access.redhat.com/errata/RHSA-2026:2220
https://access.redhat.com/errata/RHSA-2026:2231
https://access.redhat.com/errata/RHSA-2026:2271
https://access.redhat.com/errata/RHSA-2026:2286
https://access.redhat.com/security/cve/CVE-2026-0891
https://bugzilla.redhat.com/show_bug.cgi?id=2428963
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-0891.json
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*

History

30 Jun 2026, 03:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:0667 -
  • () https://access.redhat.com/errata/RHSA-2026:0694 -
  • () https://access.redhat.com/errata/RHSA-2026:0924 -
  • () https://access.redhat.com/errata/RHSA-2026:1320 -
  • () https://access.redhat.com/errata/RHSA-2026:1413 -
  • () https://access.redhat.com/errata/RHSA-2026:1414 -
  • () https://access.redhat.com/errata/RHSA-2026:1415 -
  • () https://access.redhat.com/errata/RHSA-2026:1461 -
  • () https://access.redhat.com/errata/RHSA-2026:1462 -
  • () https://access.redhat.com/errata/RHSA-2026:1471 -
  • () https://access.redhat.com/errata/RHSA-2026:1487 -
  • () https://access.redhat.com/errata/RHSA-2026:2041 -
  • () https://access.redhat.com/errata/RHSA-2026:2043 -
  • () https://access.redhat.com/errata/RHSA-2026:2044 -
  • () https://access.redhat.com/errata/RHSA-2026:2047 -
  • () https://access.redhat.com/errata/RHSA-2026:2069 -
  • () https://access.redhat.com/errata/RHSA-2026:2070 -
  • () https://access.redhat.com/errata/RHSA-2026:2073 -
  • () https://access.redhat.com/errata/RHSA-2026:2074 -
  • () https://access.redhat.com/errata/RHSA-2026:2220 -
  • () https://access.redhat.com/errata/RHSA-2026:2231 -
  • () https://access.redhat.com/errata/RHSA-2026:2271 -
  • () https://access.redhat.com/errata/RHSA-2026:2286 -
  • () https://access.redhat.com/security/cve/CVE-2026-0891 -
  • () https://bugzilla.redhat.com/show_bug.cgi?id=2428963 -
  • () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-0891.json -

13 Apr 2026, 15:17

Type Values Removed Values Added
Summary
  • (es) Errores de seguridad de memoria presentes en Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 y Thunderbird 146. Algunos de estos errores mostraron evidencia de corrupción de memoria y presumimos que con suficiente esfuerzo algunos de estos podrían haber sido explotados para ejecutar código arbitrario. Esta vulnerabilidad afecta a Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147 y Thunderbird < 140.7.
Summary (en) 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 affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7. (en) 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.

22 Jan 2026, 19:13

Type Values Removed Values Added
First Time Mozilla
Mozilla firefox
Mozilla thunderbird
CPE cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
References () https://bugzilla.mozilla.org/buglist.cgi?bug_id=1964722%2C2000981%2C2003100%2C2003278 - () https://bugzilla.mozilla.org/buglist.cgi?bug_id=1964722%2C2000981%2C2003100%2C2003278 - Broken Link
References () https://www.mozilla.org/security/advisories/mfsa2026-01/ - () https://www.mozilla.org/security/advisories/mfsa2026-01/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-03/ - () https://www.mozilla.org/security/advisories/mfsa2026-03/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-04/ - () https://www.mozilla.org/security/advisories/mfsa2026-04/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-05/ - () https://www.mozilla.org/security/advisories/mfsa2026-05/ - Vendor Advisory

15 Jan 2026, 10:16

Type Values Removed Values Added
Summary (en) 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 affects Firefox < 147 and Firefox ESR < 140.7. (en) 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 affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
References
  • () https://www.mozilla.org/security/advisories/mfsa2026-04/ -
  • () https://www.mozilla.org/security/advisories/mfsa2026-05/ -

13 Jan 2026, 15:16

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 8.1
CWE CWE-119

13 Jan 2026, 14:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-01-13 14:16

Updated : 2026-07-15 02:17


NVD link : CVE-2026-0891

Mitre link : CVE-2026-0891

CVE.ORG link : CVE-2026-0891


JSON object : View

Products Affected

mozilla

  • firefox
  • thunderbird
CWE
CWE-119

Improper Restriction of Operations within the Bounds of a Memory Buffer