DNSSEC bypass via wrong NSEC proof name
Published Jul 23, 2026 · Updated Jul 23, 2026
DNSSEC validation bypass in PowerDNS Recursor before 5.2.12, 5.3.9, and 5.4.4 allows remote attackers to make invalid wildcard answers appear secure. In checkWildcardProof(), the NSEC path asks getDenial() to test the expanded query name instead of the next-closer name, so an NSEC proving that the next-closer exists is accepted as denial evidence. A malicious authoritative server must return a legitimately signed NSEC response to a DNSSEC-validating Recursor; exploitation marks an invalid answer secure without compromising the host.
Summary
What happened
DNSSEC validation bypass in PowerDNS Recursor before 5.2.12, 5.3.9, and 5.4.4 allows remote attackers to make invalid wildcard answers appear secure. In checkWildcardProof(), the NSEC path asks getDenial() to test the expanded query name instead of the next-closer name, so an NSEC proving that the next-closer exists is accepted as denial evidence. A malicious authoritative server must return a legitimately signed NSEC response to a DNSSEC-validating Recursor; exploitation marks an invalid answer secure without compromising the host.
The record
- CVE
- CVE-2026-52688
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- PowerDNS
- Product
- PowerDNS Recursor
- Classifications
- CWE-345
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- Jul 23, 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.
- Affected versionversion=5.2.0 <5.2.12
- Affected versionversion=5.3.0 <5.3.9
- Affected versionversion=5.4.0 <5.4.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- PowerDNS Recursor NSEC wildcard-proof reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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