Buffer overflow in Mozilla Thunderbird - CVE-2021-43529

Detailed vulnerability description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when handling DER-encoded DSA or RSA-PSS signatures within Mozilla NSS library, as used in Mozilla Thunderbird. A remote attacker can send specially crafted emails with signatures encoded within CMS, S/MIME, PKCS #7, or PKCS #12, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note, this vulnerability is described separately from #VU58477 (CVE-2021-43527), as Mozilla has decided to issue different patches for Thunderbird and NSS library.

How to mitigate CVE-2021-43529

Sources

• https://www.openwall.com/lists/oss-security/2021/12/01/6
• https://bugzilla.mozilla.org/show_bug.cgi?id=1738501
• https://bugs.chromium.org/p/project-zero/issues/detail?id=2237