CVE-2026-5735Memory safety bugs fixed in Firefox 149.0.2 and Thunderbird 149.0.2
Updated under an hour ago ()
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It affects Mozilla Firefox and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 8.1 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-125, CWE-787
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Modified
- Record last updated
- Jul 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mozilla Firefox mozilla:firefox (from the name) | from 149.0.2 not affected | CNA record |
Mozilla Thunderbird mozilla:thunderbird (from the name) | from 149.0.2 not affected | CNA record |
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux | 10 | CISA ADP |
mozilla firefox mozilla:firefox | before 149.0.2 | NVD |
mozilla thunderbird mozilla:thunderbird | before 149.0.2 | NVD |
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
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.