CVE-2026-0891

Published: Jan 13, 2026Modified: Jul 15, 2026

8.1

Vector

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

Exploitability: 2.2 / Impact: 5.9

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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.

Affected (4)

Products: Mozilla: Firefox, Thunderbird

2 products

Configuration A

4 vulnerable

Vulnerable Software	Affected Versions
Mozilla Firefox	Before 147.0
Mozilla Firefox	Before 140.7.0
Mozilla Thunderbird	Before 147.0
Mozilla Thunderbird	Before 140.7.0

Related CWEs

Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

References (31)

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1964722%2C2000981%2C2003100%2C2003278

Source: security@mozilla.org

Broken Link

https://www.mozilla.org/security/advisories/mfsa2026-01/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-03/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-04/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2026-05/

Source: security@mozilla.org

Vendor Advisory

https://access.redhat.com/errata/RHSA-2026:0667

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:0694

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:0924

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1320

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1413

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1414

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1415

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1461

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1462

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1471

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:1487

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2041

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2043

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2044

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2047

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2069

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2070

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2073

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2074

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2220

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2231

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2271

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/errata/RHSA-2026:2286

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://access.redhat.com/security/cve/CVE-2026-0891

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://bugzilla.redhat.com/show_bug.cgi?id=2428963

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-0891.json

Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Timeline

No history available yet.