What’s Vulnerable › Vulnerabilities

CVE-2026-11331: Potential wildcard CNAME RPZ policy bypass

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% 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-790

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.

Affected products

• ISC BIND: from 9.16.0 through 9.18.50; from 9.20.0 through 9.20.24; from 9.21.0 through 9.21.23; from 9.16.8-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://downloads.isc.org/isc/bind9/9.21.24
• https://kb.isc.org/docs/cve-2026-11331

Get alerted when CVE-2026-11331 or the next vulnerability affects your stack