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CVE-2026-109383

CVE-2026-109383 · undici vulnerable to TLS certificate validation bypass via dropped tls options in Agent

This page contains facts from public vulnerability sources. Check the original advisory before updating.

undici is an HTTP client library for Node.js. In versions 4.0.0 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, its Agent dispatcher passes its constructor options through a JSON-based deep clone before forwarding them to each per-origin pool, and because JSON cannot represent functions, a caller-supplied tls option containing a checkServerIdentity callback is silently dropped before it reaches the TLS layer. As a result, a TLS peer whose certificate a custom checkServerIdentity was written to reject, but which passes Node's default hostname and chain checks, is silently accepted. Because Agent is the default dispatcher behind request, fetch, and setGlobalDispatcher, this affects the path most applications use, and EnvHttpProxyAgent is affected on its direct and no-proxy routes as well, while only applications that pass a function-valued tls option such as a custom checkServerIdentity for certificate or public-key pinning are at risk. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, which preserve the tls option outside the JSON clone so custom verification callbacks are forwarded unchanged, and users should upgrade to one of those versions or later. As a workaround, pass the TLS options through connect instead of tls, or for proxied destinations use requestTls and proxyTls.

CVSS 7.4 · High · EPSS 0.2% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • undici

    Versions
    • ≥ 4.0.0, < 6.29.1: Affected (semver)
    • 6.29.1: Not affected (semver)
    • ≥ 7.0.0, < 7.30.1: Affected (semver)
    • 7.30.1: Not affected (semver)
    • ≥ 8.0.0, < 8.12.2: Affected (semver)
    • 8.12.2: Not affected (semver)

    Update to 6.29.1; Update to 7.30.1; Update to 8.12.2

  • node-undici Debian:12

    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
    • 5.19.1+dfsg1+~cs20.10.9.5-1
    • 5.19.1+dfsg1+~cs20.10.9.5-2
    • 5.22.1+dfsg1+~cs20.10.10.2-1
    • 5.26.3+dfsg1+~cs23.10.12-1
    • 5.26.3+dfsg1+~cs23.10.12-2
    • 5.26.3+dfsg1+~cs23.10.12-3
    • 5.28.0+dfsg1+~cs23.11.12.3-1
    • 5.28.0+dfsg1+~cs23.11.12.3-2
    • 5.28.2+dfsg1+~cs23.11.12.3-1
    • 5.28.2+dfsg1+~cs23.11.12.3-2
    • 5.28.2+dfsg1+~cs23.11.12.3-3
    • 5.28.2+dfsg1+~cs23.11.12.3-4
    • 5.28.2+dfsg1+~cs23.11.12.3-5
    • 5.28.2+dfsg1+~cs23.11.12.3-6
    • 5.28.4+dfsg1+~cs23.12.11-1
    • 5.28.4+dfsg1+~cs23.12.11-2
    • 7.1.0+dfsg1+~cs24.12.10-1
    • 7.15.0+dfsg+~cs3.2.0-1
    • 7.15.0+dfsg+~cs3.2.0-3
    • 7.16.0+dfsg+~cs3.2.0-1
    • 7.16.0+dfsg+~cs3.2.0-2
    • 7.18.2+dfsg+~cs3.2.0-1
    • 7.2.3+dfsg1+~cs24.12.11-1
    • 7.2.3+dfsg1+~cs24.12.11-2
    • 7.24.5+dfsg+~cs3.2.0-1
    • 7.24.6+dfsg+~cs3.2.0-1
    • 7.24.6+dfsg+~cs3.2.0-2
    • 7.24.6+dfsg+~cs3.2.0-3
    • 7.3.0+dfsg1+~cs24.12.11-1
    • 7.3.0+dfsg1+~cs24.12.11-2
    • 8.10.2+dfsg+~cs3.2.2-1
    • 8.12.1+dfsg+~cs3.2.3-1
    • 8.12.2+dfsg+~cs3.2.3-1
    • 8.12.2+dfsg+~cs3.2.3-2
    • 8.5.0+dfsg+~cs3.2.0-1
    • 8.5.0+dfsg+~cs3.2.0-2
    • 8.5.0+dfsg+~cs3.2.0-3
    • 8.9.0+dfsg+~cs3.2.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-undici Debian:13

    Versions
    • 7.15.0+dfsg+~cs3.2.0-1
    • 7.15.0+dfsg+~cs3.2.0-3
    • 7.16.0+dfsg+~cs3.2.0-1
    • 7.16.0+dfsg+~cs3.2.0-2
    • 7.18.2+dfsg+~cs3.2.0-1
    • 7.24.5+dfsg+~cs3.2.0-1
    • 7.24.6+dfsg+~cs3.2.0-1
    • 7.24.6+dfsg+~cs3.2.0-2
    • 7.24.6+dfsg+~cs3.2.0-3
    • 7.3.0+dfsg1+~cs24.12.11-1
    • 7.3.0+dfsg1+~cs24.12.11-2
    • 8.10.2+dfsg+~cs3.2.2-1
    • 8.12.1+dfsg+~cs3.2.3-1
    • 8.12.2+dfsg+~cs3.2.3-1
    • 8.12.2+dfsg+~cs3.2.3-2
    • 8.5.0+dfsg+~cs3.2.0-1
    • 8.5.0+dfsg+~cs3.2.0-2
    • 8.5.0+dfsg+~cs3.2.0-3
    • 8.9.0+dfsg+~cs3.2.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-undici Debian:14

    Versions
    • 7.15.0+dfsg+~cs3.2.0-1
    • 7.15.0+dfsg+~cs3.2.0-3
    • 7.16.0+dfsg+~cs3.2.0-1
    • 7.16.0+dfsg+~cs3.2.0-2
    • 7.18.2+dfsg+~cs3.2.0-1
    • 7.24.5+dfsg+~cs3.2.0-1
    • 7.24.6+dfsg+~cs3.2.0-1
    • 7.24.6+dfsg+~cs3.2.0-2
    • 7.24.6+dfsg+~cs3.2.0-3
    • 7.3.0+dfsg1+~cs24.12.11-1
    • 7.3.0+dfsg1+~cs24.12.11-2
    • 8.10.2+dfsg+~cs3.2.2-1
    • 8.12.1+dfsg+~cs3.2.3-1
    • 8.12.2+dfsg+~cs3.2.3-1
    • 8.12.2+dfsg+~cs3.2.3-2
    • 8.5.0+dfsg+~cs3.2.0-1
    • 8.5.0+dfsg+~cs3.2.0-2
    • 8.5.0+dfsg+~cs3.2.0-3
    • 8.9.0+dfsg+~cs3.2.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-undici Ubuntu:24.04:LTS

    Versions
    • 5.22.1+dfsg1+~cs20.10.10.2-1ubuntu1
    • 5.26.3+dfsg1+~cs23.10.12-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-undici Ubuntu:26.10

    Versions
    • 7.18.2+dfsg+~cs3.2.0-1build1
    • 7.24.6+dfsg+~cs3.2.0-3
    • 8.5.0+dfsg+~cs3.2.0-2
    • 8.5.0+dfsg+~cs3.2.0-3
    • 8.9.0+dfsg+~cs3.2.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-undici Ubuntu:26.04:LTS

    Versions
    • 7.3.0+dfsg1+~cs24.12.11-2
    • 7.16.0+dfsg+~cs3.2.0-2
    • 7.18.2+dfsg+~cs3.2.0-1
    • 7.18.2+dfsg+~cs3.2.0-1build1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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