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CVE-2026-40209

CVE-2026-40209 · Denial of service via IXFR queries

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

An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.

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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