UBUNTU-CVE-2021-23993

    Dashboard / Vulnerabilities / UBUNTU-CVE-2021-23993

    UBUNTU-CVE-2021-23993

    Published: 13 Apr 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-23993

    Summary:

    Details: 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.

    References: https://ubuntu.com/security/CVE-2021-23993, https://www.mozilla.org/en-US/security/advisories/mfsa2021-13/#CVE-2021-23993, https://ubuntu.com/security/notices/USN-4995-1, https://ubuntu.com/security/notices/USN-4995-2, https://www.cve.org/CVERecord?id=CVE-2021-23993

    Affected packages

    Package

    Name: thunderbird

    Purl: pkg:deb/ubuntu/thunderbird@1:78.11.0+build1-0ubuntu0.18.04.2?arch=source&distro=bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1:78.11.0+build1-0ubuntu0.18.04.2

    Affected versions

    1:52.4.0+build1-0ubuntu2

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2021-23993 | CVE-DB