UBUNTU-CVE-2021-33500

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    UBUNTU-CVE-2021-33500

    Published: 21 May 2021Last Modified: 20 May 2026
    Upstream:
    CVE-2021-33500

    Summary:

    Details: PuTTY before 0.75 on Windows allows remote servers to cause a denial of service (Windows GUI hang) by telling the PuTTY window to change its title repeatedly at high speed, which results in many SetWindowTextA or SetWindowTextW calls. NOTE: the same attack methodology may affect some OS-level GUIs on Linux or other platforms for similar reasons.

    References: https://ubuntu.com/security/CVE-2021-33500, https://docs.ssh-mitm.at/puttydos.html, https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html, https://github.com/ssh-mitm/ssh-mitm-plugins/blob/main/ssh_mitm_plugins/ssh/putty_dos.py, https://www.cve.org/CVERecord?id=CVE-2021-33500

    Affected packages

    Package

    Name: putty

    Purl: pkg:deb/ubuntu/putty?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    0.65-2

    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-2021-33500 | CVE-DB