CVE-2026-40209: medium-severity vulnerability in PowerDNS DNSdist
Denial of service via IXFR 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 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: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%