downloads.isc.orgpatch
https://downloads.isc.org/isc/bind9/9.20.26 CVE-2026-11331
HIGH
Potential wildcard CNAME RPZ policy bypass
Record summary
CVE-2026-11331 has a selected CVSS score of 7.5 (high).
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationNone
AutomatableYes
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Jul 22, 2026 · Source: CVE List
Affected products and versions
1| Product | Source | Version range | Status |
|---|---|---|---|
BIND 9Browse ISC / BIND 9Default status: unaffected | CVE List | 9.16.0 to ≤ 9.18.50 | affected |
| 9.20.0 to ≤ 9.20.24 | affected | ||
| 9.21.0 to ≤ 9.21.23 | affected | ||
| 9.16.8-S1 to ≤ 9.18.50-S1 | affected | ||
| 9.20.9-S1 to ≤ 9.20.24-S1 | affected |
References
4downloads.isc.orgpatch
https://downloads.isc.org/isc/bind9/9.21.24 CVE-2026-11331Vendor advisory
https://kb.isc.org/docs/cve-2026-11331 nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-11331