CVE-2026-11331 Potential wildcard CNAME RPZ policy bypass
Attackers can bypass RPZ wildcard CNAME policies and potentially crash BIND 9 by sending crafted long query names, requiring RPZ configuration.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-11331?
CVE-2026-11331 is a high-severity vulnerability in ISC BIND 9, published on 22 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An attacker who knows (or guesses) that a resolver uses RPZ with wildcard CNAME policies can craft query names long enough to trigger a NAMETOOLONG error condition during RPZ processing. This is not handled correctly and may lead to defeating the RPZ rule. It also may lead to an unexpected exit of the BIND 9 software. This issue affects BIND 9 versions 9.16.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.16.8-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.
Weakness: CWE-790
Which versions are affected by CVE-2026-11331?
How do I fix CVE-2026-11331?
Apply the vendor's patch.
Is CVE-2026-11331 being exploited?
There is no known exploitation of CVE-2026-11331 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-11331, AZL-93129, BELL-CVE-2026-11331, DEBIAN-CVE-2026-11331, ECHO-d176-cede-4ce1, GHSA-8p39-mp4q-99c8 and 4 more.