What is CVE-2026-11331?

CVE-2026-11331 is a high-severity vulnerability in Isc Bind 9, classified under CWE-790. CVSS score: 7.5/10. Published 2026-07-22.

How severe is CVE-2026-11331?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Isc Bind 9

CVE-2026-11331

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.

EPSS: 0.004 (35.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Isc Bind 9 — versions 9.16.0, 9.20.0, 9.21.0

Weakness classification (CWE)

CWE-790

References

security-officer@isc.org (vendor-advisory)
security-officer@isc.org (patch)
security-officer@isc.org (patch)

Frequently asked questions

What is CVE-2026-11331?: CVE-2026-11331 is a high-severity vulnerability in Isc Bind 9, classified under CWE-790. CVSS score: 7.5/10. Published 2026-07-22.
How severe is CVE-2026-11331?: High severity. CVSS v3 base score is 7.5 out of 10.