High severity · published Apr 22, 2026
CVE-2026-33594
Outgoing DoH excessive memory allocation
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DN
DNSdist · PowerDNS
1.9.0 before 1.9.13; 2.0.0 before 2.0.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33594
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33594
Vendor Advisory
https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-04.html
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