CVE-2026-113869: Vulnerability in Mozilla Thunderbird
Description
When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a potentially exploitable crash. This vulnerability was fixed in Thunderbird 158.0.1.
CVSS v3.1
Score 5.4medium
Affected software
Mozilla
Thunderbird
pkg:github/mozilla/thunderbirdRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability arises when Thunderbird requests a security device password (such as a smartcard PIN or Primary Password) during the decryption of an S/MIME message. If the message loading process completes or is cancelled while the password prompt remains open, the message decoder object is freed prematurely while still being accessed, resulting in a use-after-free condition. This can lead to a potentially exploitable crash. Mozilla addressed this issue in Thunderbird 158.0.1.
Potential Impact
Successful exploitation can cause Thunderbird to crash due to use-after-free, which may be leveraged for further exploitation. However, no known exploits are reported in the wild. The impact is primarily a denial of service and potential memory corruption.
Mitigation Recommendations
Users should update Thunderbird to version 158.0.1 or later, where this vulnerability has been fixed. No other mitigation is required as the official fix resolves the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-10-20T19:14:55.700Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-114/","vendor":"Mozilla"}]
Threat ID: 6ad7c23c2cdf04f656561a80
Added to database: 10/20/2026, 19:34:20 UTC
Last enriched: 10/20/2026, 19:48:15 UTC
Last updated: 10/20/2026, 22:32:59 UTC
Views: 9
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