UBUNTU-CVE-2020-26890

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    UBUNTU-CVE-2020-26890

    Published: 24 Nov 2020Last Modified: 8 Sept 2025
    Upstream:
    CVE-2020-26890

    Summary:

    Details: Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events, allowing remote attackers to execute a denial of service attack against the federation and common Matrix clients. If such a malformed event is accepted into the room's state, the impact is long-lasting and is not fixed by an upgrade to a newer version, requiring the event to be manually redacted instead. Since events are replicated to servers of other room members, the impact is not constrained to the server of the event sender.

    References: https://ubuntu.com/security/CVE-2020-26890, https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f, https://www.cve.org/CVERecord?id=CVE-2020-26890

    Affected packages

    Package

    Name: matrix-synapse

    Purl: pkg:deb/ubuntu/[email protected]+dfsg-1ubuntu0.1~esm4?arch=source&distro=esm-apps/bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    0.19.2+dfsg-6

    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-2020-26890 | CVE-DB