CVE-2026-4729
CRITICAL
9.8
CVSS 3.1
Description
Memory safety bugs present in Firefox 148 and Thunderbird 148. 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 149 and Thunderbird 149.
Metadata
Severity & Metrics
9.8
CRITICAL CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC — CISA Coordinator
Affected products (2)
| Vendor | Product | Platform | Versions |
|---|---|---|---|
| Mozilla | Firefox | — | 149 ≤ * |
| Mozilla | Thunderbird | — | 149 ≤ * |
Weakness (CWE)
CVSS scores (2)
| Score | Severity | Version | Source | Vector |
|---|---|---|---|---|
| 9.8 | CRITICAL | 3.1 | adp | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 7.5 | HIGH | 3.1 | adp | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
References (3)
- Memory safety bugs fixed in Firefox 149 and Thunderbird 149 https://bugzilla.mozilla.org/buglist.cgi?bug_id=1944033%2C1997282%2C2009213%2C2011412%2C2021925%2C2022034
- https://www.mozilla.org/security/advisories/mfsa2026-20/
- https://www.mozilla.org/security/advisories/mfsa2026-23/