Description
A client can trigger excessive memory allocation by generating a lot of errors responses over a single DoQ and DoH3 connection, as some resources were not properly released until the end of the connection.
Published: 2026-04-22
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service through memory exhaustion
Action: Apply patch
AI Analysis

Impact

A client can trigger excessive memory allocation by generating a large number of error responses over a single DoQ or DoH3 connection. The flaw occurs because certain resources are not released until the connection closes, which can cause the server to consume an unbounded amount of memory and eventually become unresponsive. This weakness directly maps to CWE‑770, Excessive Resource Allocation, and it can compromise the availability of the DNS server for legitimate users. The affected vendor is PowerDNS, specifically the DNSdist product. No explicit version ranges are supplied in the advisory, so any installation built before the release of the patch described in the linked advisory remains vulnerable. The CVSS score of 5.3 indicates a moderate severity. The EPSS score is not reported, and the vulnerability is not listed in CISA’s KEV catalog, suggesting that widespread exploitation has not been observed at this time. The likely attack vector is remote, requiring an adversary to send crafted DoQ or DoH3 packets that provoke error responses, but the impact could still be substantial if an attacker can generate sufficient traffic to exhaust system memory.

Affected Systems

The affected product is PowerDNS DNSdist. No specific vulnerable versions are detailed in the advisory, so any deployment of DNSdist older than the patched release remains susceptible.

Risk and Exploitability

The CVSS score of 5.3 indicates moderate severity. EPSS is not available, so exploitation probability is unknown; the vulnerability is not listed in CISA KEV catalog, implying no confirmed widespread exploitation. The likely remote attack vector involves a client generating many error responses over a single DoQ or DoH3 connection, leading to excessive memory allocation and eventual denial of service.

Generated by OpenCVE AI on April 27, 2026 at 19:16 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Install the official DNSdist update released by PowerDNS as described in the advisory.
  • Configure firewall or access control policies to limit the number of concurrent DoQ and DoH3 connections from untrusted clients.
  • Implement server‑side rate limiting or connection timeouts to prevent memory‑burning traffic from persisting indefinitely.
  • Set up monitoring of DNSdist memory usage and establish alerts for anomalous spikes to detect potential exploitation early.

Generated by OpenCVE AI on April 27, 2026 at 19:16 UTC.

Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6235-1 dnsdist security update
History

Fri, 24 Apr 2026 19:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:powerdns:dnsdist:*:*:*:*:*:*:*:*

Wed, 22 Apr 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Powerdns
Powerdns dnsdist
Vendors & Products Powerdns
Powerdns dnsdist

Wed, 22 Apr 2026 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 22 Apr 2026 14:15:00 +0000

Type Values Removed Values Added
Description A client can trigger excessive memory allocation by generating a lot of errors responses over a single DoQ and DoH3 connection, as some resources were not properly released until the end of the connection.
Title DoQ/DoH3 excessive memory allocation
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}


Subscriptions

Powerdns Dnsdist
cve-icon MITRE

Status: PUBLISHED

Assigner: OX

Published:

Updated: 2026-04-22T14:40:28.647Z

Reserved: 2026-03-23T12:57:56.814Z

Link: CVE-2026-33595

cve-icon Vulnrichment

Updated: 2026-04-22T14:40:15.272Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-22T14:16:53.950

Modified: 2026-04-24T18:49:49.557

Link: CVE-2026-33595

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-27T19:30:12Z

Weaknesses