Authenticated NXDOMAIN forgery via incorrect NSEC3 signer validation
Published Jul 22, 2026 · Updated Jul 22, 2026
DNSSEC validation bypass in Internet Systems Consortium BIND 9 allows remote attackers to forge authenticated NXDOMAIN responses. The resolver accepts a child-zone NSEC3 record whose first label equals the parent-zone hash as a valid parent closest-encloser proof. Exploitation requires that malformed proof, and affected resolvers can falsely report names in sibling zones as nonexistent.
Summary
What happened
DNSSEC validation bypass in Internet Systems Consortium BIND 9 allows remote attackers to forge authenticated NXDOMAIN responses. The resolver accepts a child-zone NSEC3 record whose first label equals the parent-zone hash as a valid parent closest-encloser proof. Exploitation requires that malformed proof, and affected resolvers can falsely report names in sibling zones as nonexistent.
The record
- CVE
- CVE-2026-10723
- Published
- Jul 22, 2026
- Updated
- Jul 22, 2026
- Vendor
- Internet Systems Consortium
- Product
- BIND 9
- Classifications
- CWE-347, T1565.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 22, 2026CVE publishedPublication date reported by the CVE source.
- Jul 22, 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?
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- Affected versionversion=9.11.3-S1 <=9.18.50-S1
- Affected versionversion=9.18.0 <=9.18.50
- Affected versionversion=9.20.0 <=9.20.24
- Affected versionversion=9.20.9-S1 <=9.20.24-S1
- Affected versionversion=9.21.0 <=9.21.23
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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