DNS cache poisoning via out-of-zone delegation
Published Sep 16, 2026 · Updated Sep 16, 2026
Cache poisoning in Internet Systems Consortium BIND 9 allows attackers to cache data for names outside a configured zone via malformed zone data. named treats an NS or DNAME node above the zone origin as a zone cut and can follow it during recursion, caching attacker-supplied answers. Exploitation requires insertion of a malformed authoritative zone, such as through zone transfer, and a server that also provides recursion.
Summary
What happened
Cache poisoning in Internet Systems Consortium BIND 9 allows attackers to cache data for names outside a configured zone via malformed zone data. named treats an NS or DNAME node above the zone origin as a zone cut and can follow it during recursion, caching attacker-supplied answers. Exploitation requires insertion of a malformed authoritative zone, such as through zone transfer, and a server that also provides recursion.
The record
- CVE
- CVE-2026-78301
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Vendor
- Internet Systems Consortium
- Product
- BIND 9
- Classifications
- T1659
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 16, 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=9.11.0 <=9.18.50
- Affected versionversion=9.11.3-S1 <=9.18.50-S1
- Affected versionversion=9.20.0 <=9.20.27
- Affected versionversion=9.20.9-S1 <=9.20.27-S1
- Affected versionversion=9.21.0 <=9.21.25
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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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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