UBUNTU-CVE-2026-121506

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    UBUNTU-CVE-2026-121506

    Published: 3 Nov 2026Last Modified: 5 Nov 2026
    Upstream:
    CVE-2026-121506

    Summary:

    Details: An out-of-bounds read and write in NTS client extension field parsing (extens_client_recv) in NTPsec before 1.2.5 allows a remote attacker who can send NTP server-mode replies to an NTS client to corrupt heap memory and crash ntpd, and, combined with the NTS-KE client out-of-bounds read fixed in 1.2.4, to bypass NTS authentication and set the client's time, via an NTS Authenticator and Encrypted Extension Fields field whose nonce length exceeds the field.

    References: https://ubuntu.com/security/CVE-2026-121506, https://www.cve.org/CVERecord?id=CVE-2026-121506, https://gitlab.com/NTPsec/ntpsec/-/commit/0a36941e499d533dfbc3fb6b1fcd8c367679d719, https://gitlab.com/NTPsec/ntpsec/-/work_items/902

    Affected packages

    Package

    Name: ntpsec

    Purl: pkg:deb/ubuntu/ntpsec?arch=source&distro=bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    1.0.0+dfsg1-1
    1.0.0+dfsg1-3

    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-2026-121506 | CVE-DB