PSF-2022-6

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    PSF-2022-6

    Published: 7 Mar 2022Last Modified: 9 Oct 2025

    Summary: CVE-2021-3733: ReDoS in urllib.request

    Details: There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

    References: https://access.redhat.com/security/cve/cve-2021-3733, https://bugs.python.org/issue43075

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -3fbe96123aeb66664fa547a8f6022efa2dc8788f

    Affected versions

    2.5

    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
    PSF-2022-6 | CVE-DB