CVE-2026-100819Sandbox escape due to incorrect boundary conditions in the XPCOM component
Updated under an hour ago ()
Does this affect you?
It affects Mozilla Firefox 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 0.26%, higher than 16% of scored CVEs.
Do this next
Free account, 1 product
Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
- 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-119
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.26% (percentile 16)
- Assigned by
- mozilla
- NVD analysis
- Analyzed
- Record last updated
- Sep 30, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mozilla Firefox mozilla:firefox (from the name) | 115.42 builds before 115.* not affected; 140.17 builds before 140.* not affected; 153.4 builds before 153.* not affected; from 157 not affected | CNA record |
Mozilla Thunderbird mozilla:thunderbird (from the name) | 140.17 builds before 140.* not affected; 153.4 builds before 153.* not affected; from 157 not affected | CNA record |
mozilla firefox mozilla:firefox | before 115.42.0; from 116.0 before 140.17.0; from 141.0 before 153.4.0; from 154.0.0 before 157.0.0 | NVD |
mozilla thunderbird mozilla:thunderbird | before 140.17.0; from 141.0 before 153.4.0; from 154.0 before 157.0 | NVD |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2071069permissions-required
- https://www.mozilla.org/security/advisories/mfsa2026-100/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-101/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-102/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-103/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-97/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-98/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-99/vendor-advisory
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.