Threats Tagged 'cve-2026-40211'

Multiple security vulnerabilities were fixed in dnsdist with the update to version 1.9.15. These include issues causing invalid output in the Prometheus endpoint, delays in processing DNS over HTTP/3 queries, stuck outgoing TCP connections, out-of-bounds reads leading to crashes or memory leaks, exceptions causing out-of-memory conditions, improper handling of crafted EDNS OPT records, and denial-of-service via unlimited memory allocation in the internal web server.

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.

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.