DEBIAN-CVE-2026-84961

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    DEBIAN-CVE-2026-84961

    Published: 4 Sept 2026Last Modified: 16 Sept 2026
    Upstream:

    Summary:

    Details: undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value as JSON. Because JSON cannot represent functions, any function-valued TLS option, such as a caller-supplied checkServerIdentity callback or a custom connector inside the connect option, is silently discarded before it reaches the TLS layer. As a result a peer whose certificate the application's custom checkServerIdentity was written to reject, but which still passes Node's default hostname and chain checks, is accepted when reached through BalancedPool. The Client, Pool, and Agent dispatchers are not affected because they extract the connect and tls options before cloning. This affects undici versions from 7.24.1 up to 7.29.1 and from 8.0.0 up to 8.10.2, and only when the application supplies a function-valued connect or tls option to BalancedPool. Users should upgrade to undici 7.29.1 or 8.10.2.

    Affected packages

    Package

    Name: node-undici

    Purl: pkg:deb/debian/node-undici?arch=source&distro=bookworm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    5.15.0+dfsg1+~cs20.10.9.3-1
    5.15.0+dfsg1+~cs20.10.9.3-1+deb12u1
    5.15.0+dfsg1+~cs20.10.9.3-1+deb12u2
    5.15.0+dfsg1+~cs20.10.9.3-1+deb12u3
    5.15.0+dfsg1+~cs20.10.9.3-1+deb12u4

    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
    DEBIAN-CVE-2026-84961 | CVE-DB