What’s Vulnerable › Vulnerabilities

CVE-2026-113869: Use-after-free in S/MIME decryption during a security device password prompt

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-20 · updated 2026-10-27
• Weakness: CWE-416

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 and Thunderbird 153.6.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2075530
• https://www.mozilla.org/security/advisories/mfsa2026-114/
• https://www.mozilla.org/security/advisories/mfsa2026-122/

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