Medium 5.4Published Oct 20, 2026

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

Updated under an hour ago (2026-10-21 19:00 UTC)

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It affects Mozilla Thunderbird. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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: 5.4 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: mozilla
NVD analysis: Received
Record last updated: Oct 20, 2026
First seen by InfoSec Signals: Oct 20, 2026

Affected products

Affected products

Mozilla Thunderbird mozilla:thunderbird (from the name)	from 158.0.1 not affected	CNA record

References

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

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.