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    CVE-2026-40211

    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.

    Published:Jun 25, 2026
    Last Modified:Jun 26, 2026
    EPS:Jun 25, 2026
    EPSS Score:
    CVSS Score:5.3

    Affected Products

    Vendor
    Powerdns
    Product
    Dnsdist

    Exploits

    No exploit reference

    Related CVEs

    CVE-2026-42004 (CVSS 3.7) — An attacker can send a crafted EDNS OPT record that will be ignored by DNSdist’s filtering rules, but will be …
    CVE-2026-40210 (CVSS 4.8) — An out-of-bounds read might happen when SetMacAddrAction is used, potentially resulting in uninitialized memor…
    CVE-2026-40209 (CVSS 5.3) — An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs inst…
    CVE-2026-40208 (CVSS 3.7) — An attacker might be able to delay the processing of DoH3 queries by sending DoH3 GET queries with an invalid …
    CVE-2026-40011 (CVSS 3.7) — An attacker sending a large number of crafted DNS queries might be able to trigger a dynamic block being inser…
    CVE-2026-33593 (CVSS 7.5) — A client can trigger a divide by zero error leading to crash by sending a crafted DNSCrypt query.…
    CVE-2026-33594 (CVSS 5.3) — A client can trigger excessive memory allocation by generating a lot of queries that are routed to an overload…
    CVE-2026-33595 (CVSS 5.3) — A client can trigger excessive memory allocation by generating a lot of errors responses over a single DoQ and…
    CVE-2026-33597 (CVSS 3.7) — PRSD detection denial of service…
    CVE-2026-33596 (CVSS 3.1) — A client might theoretically be able to cause a mismatch between queries sent to a backend and the received re…

    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