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CVE-2026-40211

CVE-2026-40211 · Denial of service via crafted DoH3 queries

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

An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.

CVSS 5.3 · Medium · EPSS 0.7% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • dnsdist

    Versions
    • ≥ 1.9.0, < 1.9.15: Affected (semver)
    • ≥ 2.0.0, < 2.0.7: Affected (semver)

    Update to 1.9.15; Update to 2.0.7

  • dnsdist Debian:12

    Versions
    • 1.7.3-2
    • 1.8.0-1
    • 1.8.1-1
    • 1.8.2-1
    • 1.8.2-2
    • 1.8.2-3
    • 1.8.3-1
    • 1.8.3-2
    • 1.8.3-3
    • 1.9.10-1
    • 1.9.3-1
    • 1.9.4-1
    • 1.9.5-1
    • 1.9.6-1
    • 1.9.8-1
    • 1.9.9-1
    • 2.0.0-1
    • 2.0.0-2
    • 2.0.0-3
    • 2.0.0-4
    • 2.0.0-5
    • 2.0.0-6
    • 2.0.0~rc1-1
    • 2.0.0~rc1-2
    • 2.0.0~rc2-1
    • 2.0.1-1
    • 2.0.2-1
    • 2.0.3-1
    • 2.0.4-1
    • 2.0.5-1
    • 2.0.5-2
    • 2.0.5-3
    • 2.0.6-1
    • 2.1.0-1
    • 2.1.0-2
    • 2.1.1-1
    • 2.1.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Debian:13

    Versions
    • 1.9.10-1
    • 1.9.10-1+deb13u1
    • 1.9.14-0+deb13u1
    Affected ranges
    • ECOSYSTEM: < 1.9.15-0+deb13u1

    Update to 1.9.15-0+deb13u1

  • dnsdist Debian:14

    Versions
    • 1.9.10-1
    • 2.0.0-1
    • 2.0.0-2
    • 2.0.0-3
    • 2.0.0-4
    • 2.0.0-5
    • 2.0.0-6
    • 2.0.0~rc1-1
    • 2.0.0~rc1-2
    • 2.0.0~rc2-1
    • 2.0.1-1
    • 2.0.2-1
    • 2.0.3-1
    • 2.0.4-1
    • 2.0.5-1
    • 2.0.5-2
    • 2.0.5-3
    • 2.0.6-1
    Affected ranges
    • ECOSYSTEM: < 2.1.0-1

    Update to 2.1.0-1

  • dnsdist Ubuntu:16.04:LTS

    Versions
    • 1.0.0~alpha2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:Pro:18.04:LTS

    Versions
    • 1.2.0-1
    • 1.2.0-3
    • 1.2.1-1
    • 1.2.1-1build1
    • 1.2.1-1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:Pro:20.04:LTS

    Versions
    • 1.4.0~rc3-1
    • 1.4.0-1
    • 1.4.0-1build1
    • 1.4.0-1build2
    • 1.4.0-1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:Pro:22.04:LTS

    Versions
    • 1.5.1-3build2
    • 1.6.1-1build1
    • 1.6.1-1ubuntu0.1~esm1
    • 1.6.1-1ubuntu0.1~esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:Pro:24.04:LTS

    Versions
    • 1.8.0-1
    • 1.8.2-1
    • 1.8.2-2
    • 1.8.2-3
    • 1.8.3-1
    • 1.8.3-2
    • 1.8.3-2build1
    • 1.8.3-2build2
    • 1.8.3-2ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:25.10

    Versions
    • 1.9.8-1
    • 1.9.10-1
    • 1.9.10-1ubuntu0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:26.10

    Versions
    • 2.0.2-1build1
    • 2.0.5-2ubuntu1
    • 2.0.5-2ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • dnsdist Ubuntu:26.04:LTS

    Versions
    • 1.9.10-1
    • 2.0.1-1
    • 2.0.2-1
    • 2.0.2-1build1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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