CVE-2026-0398Network attack vector

Service interruption via unbounded DNS response processing

Published Feb 9, 2026 · Updated Feb 9, 2026

Resource exhaustion in the synchronous resolver of PowerDNS Recursor allows remote attackers to interrupt service via crafted DNS zones. The resolver accepts unbounded cumulative response bytes and oversized record or packet-cache entries, allowing one query to drive large memory allocation. Attackers must publish a crafted zone and induce an allowed client query; unreachable CNAME records can also be admitted to cache, poisoning later answers.

CVSS severity5.3
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in the synchronous resolver of PowerDNS Recursor allows remote attackers to interrupt service via crafted DNS zones. The resolver accepts unbounded cumulative response bytes and oversized record or packet-cache entries, allowing one query to drive large memory allocation. Attackers must publish a crafted zone and induce an allowed client query; unreachable CNAME records can also be admitted to cache, poisoning later answers.

The record

CVE
CVE-2026-0398
Published
Feb 9, 2026
Updated
Feb 9, 2026
Vendor
PowerDNS
Product
PowerDNS Recursor
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.1.0 <5.1.10
  2. Affected versionversion=5.2.0 <5.2.8
  3. Affected versionversion=5.3.0 <5.3.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PowerDNS · PowerDNS Recursorversion=5.1.0 <5.1.10; version=5.2.0 <5.2.8; version=5.3.0 <5.3.5

Published CVSS scores

5.3PowerDNSCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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