High severity · published Aug 18, 2026
CVE-2026-74965
Privilege escalation in the Shell Integration component
8.8
CVSS
0.4%
EPSS
No
On KEV
Description
Privilege escalation in the Shell Integration component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 140.14.0; before 154.0.0; 153.0 · source: NVD
TH
Thunderbird · Mozilla
before 140.14.0; before 154.0; 153.0 before 153.1.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-74965
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-74965
Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=2053455
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-74/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-76/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-77/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-78/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-79/
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