Unexpected Program Termination in BIND 9 by Internet Systems Consortium
CVE-2026-12617

7.5HIGH

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
22 July 2026

Badges

👾 Exploit Exists

What is CVE-2026-12617?

A vulnerability in BIND 9 can cause unexpected program termination due to specific query response ordering. If a client queries for a DNAME and an A record, and the server delays the DNAME response while responding positively to the A record, a failure may occur. Similarly, querying a CNAME and A record simultaneously may lead to the same issue, particularly if the server provides a self-referential CNAME after a delayed response. This impacts server reliability and could affect DNS resolution processes.

Affected Version(s)

BIND 9 9.18.0 <= 9.18.50

BIND 9 9.20.0 <= 9.20.24

BIND 9 9.18.11-S1 <= 9.18.50-S1

References

https://kb.isc.org/docs/cve-2026-12617
vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.26
patch

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

ISC would like to thank Qifan Zhang of Palo Alto Networks for bringing this vulnerability to our attention.
.