Mozilla Foundation Security Advisory 2026-26
Security Vulnerabilities fixed in Firefox ESR 115.34.1
- Announced
- April 7, 2026
- Impact
- low
- Products
- Firefox ESR
- Fixed in
-
- Firefox ESR 115.34.1
#CVE-2026-5731: Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2
- Reporter
- Brian Grinstead, Christian Holler, Tom Schuster and the Mozilla Fuzzing Team
- Impact
- high
Description
Memory safety bugs present in Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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.