VulnerabilityModified
CVE-2026-5735
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.
CRITICAL 9.8EPSS 0.26%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Memory safety bugs present in 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. This vulnerability was fixed in Firefox 149.0.2 and Thunderbird 149.0.2.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.26% probability · 17th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787, CWE-125
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2025475%2C2025477Broken Link, Issue Tracking
- https://www.mozilla.org/security/advisories/mfsa2026-25/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-28/
- https://access.redhat.com/security/cve/CVE-2026-5735
- https://bugzilla.redhat.com/show_bug.cgi?id=2455904
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5735.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.