CVE-2021-23993

An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird < 78.9.1.

• CWE-347

• https://bugzilla.mozilla.org/show_bug.cgi?id=1666360Issue Tracking, Permissions Required, Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-13/Release Notes, Vendor Advisory
• https://bugzilla.mozilla.org/show_bug.cgi?id=1666360Issue Tracking, Permissions Required, Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-13/Release Notes, Vendor Advisory

Published

Jun 24, 2021

Last Modified

Jun 17, 2026

Status

Modified

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