High 8.8Published Sep 29, 2026

CVE-2026-100801Privilege escalation in the DLL Services component

Updated under an hour ago (Oct 28, 2026, 6:40 AM ET)

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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 0.25%, higher than 15% of scored CVEs.

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Every CVE for Mozilla Thunderbird

Exploited in the last 30 days

Privilege escalation in the DLL Services component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 159, Firefox ESR 153.6, Thunderbird 159, Thunderbird 153.6, Firefox 157, and Firefox ESR 140.17.

CVSS: 8.8 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-269
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.25% (percentile 15)
Assigned by: mozilla
NVD analysis: Modified
Record last updated: Oct 27, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Mozilla Thunderbird mozilla:thunderbird (from the name)	140.17 builds before 140.* not affected; 153.4 builds before 153.* not affected; 153.6 builds before 153.* not affected; from 157 through 157.* not affected; from 159 not affected	CNA record
Mozilla Firefox mozilla:firefox (from the name)	140.17 builds before 140.* not affected; 153.4 builds before 153.* not affected; 153.6 builds before 153.* not affected; from 157 through 157.* not affected; from 159 not affected	CNA record
mozilla firefox mozilla:firefox	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

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2057112	permissions-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/mfsa2026-118/
https://www.mozilla.org/security/advisories/mfsa2026-120/
https://www.mozilla.org/security/advisories/mfsa2026-121/
https://www.mozilla.org/security/advisories/mfsa2026-122/
https://www.mozilla.org/security/advisories/mfsa2026-97/	vendor-advisory
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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.