UBUNTU-CVE-2021-20235

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    UBUNTU-CVE-2021-20235

    Published: 1 Apr 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-20235
    Aliases:
    USN-4920-1

    Summary:

    Details: There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality.

    References: https://ubuntu.com/security/CVE-2021-20235, https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6, https://ubuntu.com/security/notices/USN-4920-1, https://www.cve.org/CVERecord?id=CVE-2021-20235

    Affected packages

    Package

    Name: zeromq3

    Purl: pkg:deb/ubuntu/[email protected]+esm2?arch=source&distro=esm-apps/bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -4.2.5-1ubuntu0.2+esm2

    Affected versions

    4.2.1-4ubuntu1
    4.2.2-1ubuntu2
    4.2.3-1
    4.2.3-1build1
    4.2.5-1
    4.2.5-1ubuntu0.1
    4.2.5-1ubuntu0.2
    4.2.5-1ubuntu0.2+esm1

    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-2021-20235 | CVE-DB