🛡️ CVE-2021-43529 on Debian — thunderbird

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

Thunderbird versions prior to 91.3.0 are vulnerable to the heap overflow described in CVE-2021-43527 when processing S/MIME messages. Thunderbird versions 91.3.0 and later will not call the vulnerable code when processing S/MIME messages that contain certificates with DER-encoded DSA or RSA-PSS signatures.

Distribution advisory

This page covers CVE-2021-43529 as tracked by Debian, for the package thunderbird. The fix is available in version 1:91.3.0-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

DEBIAN-CVE-2021-43529 is recorded against 1 package.

thunderbird (fixed in 1:91.3.0-1)

Timeline and source

Published on 16 February 2023 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-43529 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Ubuntu

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2023-02-16

Updated 2026-08-20

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
thunderbird	—	1:91.3.0-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2021-43529

🔗 NVD 🔗 Mitre

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