BIND 9 Resolver Vulnerability in ISC Software
CVE-2026-11331

7.5HIGH

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
22 July 2026

Badges

👾 Exploit Exists

What is CVE-2026-11331?

A security issue in BIND 9 arises when an attacker exploits resolver configurations using RPZ with wildcard CNAME policies. By crafting excessively long query names, the attacker can provoke a NAMETOOLONG error during RPZ processing. This situation is inadequately handled, potentially nullifying the intended RPZ rules and leading to unexpected behavior in BIND 9 software, including possible exits from the application. It's essential to apply the appropriate patches to safeguard against this issue.

Affected Version(s)

BIND 9 9.16.0 <= 9.18.50

BIND 9 9.20.0 <= 9.20.24

BIND 9 9.21.0 <= 9.21.23

References

https://kb.isc.org/docs/cve-2026-11331
vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.26
patch
https://downloads.isc.org/isc/bind9/9.21.24
patch

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
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 Laith Mash'al (0xmshal) for bringing this vulnerability to our attention.
.