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UK Cyber Defence
VulnerabilityModified

CVE-2021-29950

This vulnerability affects Thunderbird < 78.8.1.

HIGH 7.5EPSS 0.85%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.85%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Thunderbird unprotects a secret OpenPGP key prior to using it for a decryption, signing or key import task. If the task runs into a failure, the secret key may remain in memory in its unprotected state. This vulnerability affects Thunderbird < 78.8.1.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
0.85% probability · 58th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-312
Affected
mozilla/thunderbird
Source
security@mozilla.org
EPSS trend
0%3%5%26 October 2026: 0.85%26 October 202626 October 2026

EPSS 0.9% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.