USN-6560-1

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    USN-6560-1

    Published: 19 Dec 2023Last Modified: 27 Apr 2026

    Summary: openssh vulnerabilities

    Details: Fabian Bäumer, Marcus Brinkmann, Jörg Schwenk discovered that the SSH protocol was vulnerable to a prefix truncation attack. If a remote attacker was able to intercept SSH communications, extension negotiation messages could be truncated, possibly leading to certain algorithms and features being downgraded. This issue is known as the Terrapin attack. This update adds protocol extensions to mitigate this issue. (CVE-2023-48795) Luci Stanescu discovered that OpenSSH incorrectly added destination constraints when smartcard keys were added to ssh-agent, contrary to expectations. This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04. (CVE-2023-28531)

    Affected packages

    Package

    Name: openssh

    Purl: pkg:deb/ubuntu/openssh@1:8.2p1-4ubuntu0.10?arch=source&distro=focal

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1:8.2p1-4ubuntu0.10

    Affected versions

    1:8.0p1-6build1

    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
    USN-6560-1 | CVE-DB