Review reviewHigh

CVE-2026-12617

ISC BIND 9

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...

CVSS: 7.5
EPSS: 0.49%
CISA KEV: Not listed
Published: 2026.07.23

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.49%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: ISC BIND 9
Affected versions: >= 9.18.0 <= 9.18.50, >= 9.20.0 <= 9.20.24, >= 9.18.11-S1 <= 9.18.50-S1, >= 9.20.9-S1 <= 9.20.24-S1
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that ISC BIND 9 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-617