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PowerDNS Recursor CVE-2026-33256

| EUVDEUVD-2026-24719 MEDIUM
Allocation of Resources Without Limits or Throttling (CWE-770)
2026-04-22 security@open-xchange.com GHSA-f4c2-g8rq-pq9h
5.3
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
5.3 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
SUSE
MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Lifecycle Timeline

6
Patch released
Apr 27, 2026 - 17:04 nvd
Patch available
Analysis Generated
Apr 22, 2026 - 13:09 vuln.today
Patch available
Apr 22, 2026 - 11:16 EUVD
EUVD ID Assigned
Apr 22, 2026 - 10:22 euvd
EUVD-2026-24719
Analysis Generated
Apr 22, 2026 - 10:22 vuln.today
CVE Published
Apr 22, 2026 - 10:16 nvd
MEDIUM 5.3

DescriptionCVE.org

An attacker can send a web request that causes unlimited memory allocation in the internal web server, leading to a denial of service. The internal web server is disabled by default.

AnalysisAI

Denial of service via unlimited memory allocation in PowerDNS Recursor's internal web server affects versions 5.2.0-5.2.8, 5.3.0-5.3.5, and 5.4.0. An unauthenticated remote attacker can send a crafted web request to exhaust server memory when the internal web server is enabled, causing service unavailability. No public exploit code or active exploitation has been identified, but patch versions are available from the vendor.

Technical ContextAI

PowerDNS Recursor is a DNS recursive resolver that includes an optional internal web server for statistics and management queries. The vulnerability stems from improper memory management in the web server request handling, allowing an attacker to trigger unbounded memory allocation through a crafted HTTP request. The attack surface is limited because the internal web server is disabled by default, but administrators who enable it for monitoring or API access expose their infrastructure to this denial-of-service vector. The root cause likely involves insufficient bounds checking or memory limit enforcement in request processing, though specific CWE classification was not provided.

RemediationAI

Upgrade to PowerDNS Recursor 5.2.9, 5.3.6, 5.4.1, or later, depending on your current version branch. Full patch details and upgrade instructions are available in the vendor security advisory at https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-03.html. If immediate patching is not possible, disable the internal web server by setting webserver=no and api=no in the Recursor configuration file (typically /etc/powerdns/recursor.conf), then restart the service. This mitigation eliminates the attack surface entirely but removes access to the web-based statistics interface and REST API; assess operational impact before applying. Network-level mitigation via firewall rules blocking access to the web server port (default 8082) provides partial protection but is not a substitute for patching, as the vulnerability allows exploitation from any network-accessible attacker.

CVE-2016-5427 HIGH
7.5 Sep 21

PowerDNS (aka pdns) Authoritative Server before 3.4.10 does not properly handle a . Rated high severity (CVSS 7.5), this

CVE-2016-5426 HIGH
7.5 Sep 21

PowerDNS (aka pdns) Authoritative Server before 3.4.10 allows remote attackers to cause a denial of service (backend CPU

CVE-2019-3871 HIGH POC
8.8 Mar 21

A vulnerability was found in PowerDNS Authoritative Server before 4.0.7 and before 4.1.7. Rated high severity (CVSS 8.8)

CVE-2021-36754 HIGH POC
7.5 Jul 30

PowerDNS Authoritative Server 4.5.0 before 4.5.1 allows anybody to crash the process by sending a specific query (QTYPE

CVE-2012-1193 MEDIUM POC
6.4 Feb 17

The resolver in PowerDNS Recursor (aka pdns_recursor) 3.3 overwrites cached server names and TTL values in NS records du

CVE-2020-24698 CRITICAL
9.8 Oct 02

An issue was discovered in PowerDNS Authoritative through 4.3.0 when --enable-experimental-gss-tsig is used. Rated criti

CVE-2019-3807 CRITICAL
9.8 Jan 29

An issue has been found in PowerDNS Recursor versions 4.1.x before 4.1.9 where records in the answer section of response

CVE-2017-7557 HIGH
8.8 Aug 22

dnsdist version 1.1.0 is vulnerable to a flaw in authentication mechanism for REST API potentially allowing CSRF attack.

CVE-2020-10030 HIGH
8.8 May 19

An issue has been found in PowerDNS Recursor 4.1.0 up to and including 4.3.0. Rated high severity (CVSS 8.8), this vulne

CVE-2026-42000 HIGH
8.6 May 21

Denial of service in PowerDNS Authoritative DNS server (versions 4.9.0-4.9.14 and 5.0.0-5.0.4) arises from insufficient

CVE-2026-24028 HIGH
8.2 Mar 31

Out-of-bounds read in PowerDNS dnsdist allows unauthenticated remote attackers to trigger denial of service or potential

CVE-2025-59023 HIGH
8.2 Feb 09

Crafted delegations or IP fragments can poison cached delegations in Recursor. [CVSS 8.2 HIGH]

Vendor StatusVendor

SUSE

Severity: Medium

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CVE-2026-33256 vulnerability details – vuln.today

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