CVE-2026-40211: medium-severity vulnerability in PowerDNS DNSdist
Denial of service via crafted DoH3 queries
Published
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.7%
exploitation probability
0.7%top 48% of all CVEs
observed exploitation
nono source reports it
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
PowerDNS · DNSdistRelated CVEs — PowerDNS DNSdist
In the same product, most dangerous first.
CVE-2026-33598MEDIUMOut-of-bounds read in cache inspection via LuaEPSS 2.8%CVE-2025-30194HIGHDenial of service via crafted DoH exchangeEPSS 2.3%CVE-2026-27853MEDIUMOut-of-bounds write when rewriting large DNS packetsEPSS 1.5%CVE-2026-27854MEDIUMUse after free when parsing EDNS options in LuaEPSS 1.3%CVE-2026-33602MEDIUMOff-by-one access when processing crafted UDP responsesEPSS 1.2%CVE-2024-25581HIGHTransfer requests received over DoH can lead to a denial of service in DNSdistEPSS 1.1%