PYSEC-2026-843

    Dashboard / Vulnerabilities / PYSEC-2026-843

    PYSEC-2026-843

    Published: 6 Jul 2026Last Modified: 7 Jul 2026

    Summary: Matrix Sydent mishandles emails

    Details: util/emailutils.py in Matrix Sydent before 1.0.2 mishandles registration restrictions that are based on e-mail domain, if the allowed_local_3pids option is enabled. This occurs because of potentially unwanted behavior in Python, in which an email.utils.parseaddr call on [email protected]@good.example.com returns the [email protected] substring.

    References: https://nvd.nist.gov/vuln/detail/CVE-2019-11340, https://github.com/matrix-org/sydent/commit/4e1cfff53429c49c87d5c457a18ed435520044fc, https://github.com/matrix-org/sydent/compare/7c002cd...09278fb, https://matrix.org/blog/2019/04/18/security-update-sydent-1-0-2, https://twitter.com/matrixdotorg/status/1118934335963500545, https://pypi.org/project/matrix-sydent, https://github.com/advisories/GHSA-q9h8-gpw5-c95c

    Affected packages

    Package

    Name: matrix-sydent

    Purl: pkg:pypi/matrix-sydent

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1.0.2

    Affected versions

    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