CVE-2026-12617
Record ordering based unexpected exit with CNAME or DNAME
- State
- Published
- Severity
- 7.5 High
- Published
- Jul 22, 2026
- Updated
- Jul 22, 2026
- Reserved
- Jun 18, 2026
Description
The issue is unexpected program termination based on ordering and/or specific content in responses to queries for CNAME or DNAME, and A records. Specifically, if a client queries for a DNAME and A record below the DNAME to the resolver, and the authoritative server responds positively to the A query but delays the DNAME response and later responds negatively, `named` may quit unexpectedly. Or, if a client queries for a CNAME and A record for the same name to the resolver, and the authoritative server responds positively to the A query but delays the CNAME response and later responds with a self-referential CNAME, the same failure may occur. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.24, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | isc |
Weaknesses
- CWE-617 Reachable Assertion
Affected Products
| Product | Versions |
|---|---|
BIND 9ISC |
|
References
- CVE-2026-12617vendor-advisory
- https://downloads.isc.org/isc/bind9/9.20.26patch
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