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Critical 9.6Published Sep 29, 2026
CVE-2026-100804Sandbox escape due to use-after-free in the Preferences: Backend component
Updated under an hour ago ()
Does this affect you?
It affects Mozilla Thunderbird and 1 other product. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.30%, higher than 21% of scored CVEs.
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Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
- CVSS
- 9.6 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-416
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.30% (percentile 21)
- Assigned by
- mozilla
- NVD analysis
- Undergoing Analysis
- Record last updated
- Sep 30, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mozilla Thunderbird mozilla:thunderbird (from the name) | from 157 not affected | CNA record |
Mozilla Firefox mozilla:firefox (from the name) | from 157 not affected | CNA record |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2058647
- https://www.mozilla.org/security/advisories/mfsa2026-101/
- https://www.mozilla.org/security/advisories/mfsa2026-97/
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.