What’s Vulnerable › Vulnerabilities

CVE-2026-12617: Record ordering based unexpected exit with CNAME or DNAME

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-22 · updated 2026-10-24
• Weakness: CWE-617

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.

Affected products

• ISC BIND: from 9.18.0 through 9.18.50; from 9.20.0 through 9.20.24; from 9.18.11-S1 through 9.18.50-S1; from 9.20.9-S1 through 9.20.24-S1

References

• https://downloads.isc.org/isc/bind9/9.20.26
• https://kb.isc.org/docs/cve-2026-12617

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