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dnsdist vulnerabilities

Vulnerabilities published for dnsdist in the last 30 days: 0. Listed in the KEV catalogue: 0.

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Vulnerabilities: 34

  1. CVE-2026-42004

    Low · CVSS 3.7EPSS 0.22%Fix available

    EDNS options smuggling

    An attacker can send a crafted EDNS OPT record that will be ignored by DNSdist’s filtering rules, but will be rewritten as a valid OPT record when EDNS Client Subnet is inserted, causing the backend to see the EDNS option(s) that DNSdist did not filter.

    • Update to 1.9.15-0+deb13u1
    Published Updated
  2. CVE-2026-40211

    Medium · CVSS 5.3EPSS 0.7%Fix available

    Denial of service via crafted DoH3 queries

    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.

    • Update to 1.9.15-0+deb13u1
    Published Updated
  3. CVE-2026-40209

    Medium · CVSS 5.3EPSS 0.7%Fix available

    Denial of service via IXFR queries

    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.

    • Update to 1.9.15-0+deb13u1
    Published Updated
  4. CVE-2026-40011

    Low · CVSS 3.7EPSS 0.22%Fix available

    Prometheus denial of service via crafted DNS queries

    An attacker sending a large number of crafted DNS queries might be able to trigger a dynamic block being inserted with a value causing invalid output to be produced in the prometheus endpoint. The prometheus endpoint will then be rejected by the scraper until the dynamic block expires.

    • Update to 1.9.15-0+deb13u1
    Published Updated
  5. CVE-2026-42005

    Medium · CVSS 4.3EPSS 0.62%Fix available

    Insufficient input validation of internal web server

    An attacker can send a web request that causes unlimited memory allocation in the internal web server, leading to a denial of service. The internal web server is disabled by default.

    • Update to 1.9.15-0+deb13u1
    Published Updated
  6. CVE-2026-33594

    Medium · CVSS 5.3EPSS 0.8%Fix available

    Outgoing DoH excessive memory allocation

    A client can trigger excessive memory allocation by generating a lot of queries that are routed to an overloaded DoH backend, causing queries to accumulate into a buffer that will not be released until the end of the connection.

    • Update to 1.9.14-0+deb13u1
    Published Updated
  7. CVE-2026-33595

    Medium · CVSS 5.3EPSS 0.8%Fix available

    DoQ/DoH3 excessive memory allocation

    A client can trigger excessive memory allocation by generating a lot of errors responses over a single DoQ and DoH3 connection, as some resources were not properly released until the end of the connection.

    • Update to 1.9.14-0+deb13u1
    Published Updated
  8. CVE-2026-33596

    Low · CVSS 3.1EPSS 0.39%Fix available

    TCP backend stream ID overflow

    A client might theoretically be able to cause a mismatch between queries sent to a backend and the received responses by sending a flood of perfectly timed queries that are routed to a TCP-only or DNS over TLS backend.

    • Update to 1.9.14-0+deb13u1
    Published Updated
  9. CVE-2026-33599

    Low · CVSS 3.1EPSS 0.8%Fix available

    Out-of-bounds read in service discovery

    A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request, when requested via either the autoUpgrade (Lua) option to newServer or auto_upgrade (YAML) settings. DDR upgrade is not enabled by default.

    • Update to 1.9.14-0+deb13u1
    Published Updated
  10. CVE-2026-33602

    Medium · CVSS 6.5EPSS 1.18%Fix available

    Off-by-one access when processing crafted UDP responses

    A rogue backend can send a crafted UDP response with a query ID off by one related to the maximum configured value, triggering an out-of-bounds write leading to a denial of service.

    • Update to 1.9.14-0+deb13u1
    Published Updated
  11. CVE-2026-33254

    Medium · CVSS 5.3EPSS 0.8%Fix available

    Resource exhaustion via DoQ/DoH3 connections

    An attacker can create a large number of concurrent DoQ or DoH3 connections, causing unlimited memory allocation in DNSdist and leading to a denial of service. DOQ and DoH3 are disabled by default.

    • Update to 1.9.14-0+deb13u1
    Published Updated
  12. CVE-2026-27854

    Medium · CVSS 4.8EPSS 1.34%Fix available

    Use after free when parsing EDNS options in Lua

    An attacker might be able to trigger a use-after-free by sending crafted DNS queries to a DNSdist using the DNSQuestion:getEDNSOptions method in custom Lua code. In some cases DNSQuestion:getEDNSOptions might refer to a version of the DNS packet that has been modified, thus triggering a use-after-free and potentially a crash resulting in denial of service.

    • Update to 1.9.14-0+deb13u1
    Published Updated

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