CVE-2026-11331

Potential wildcard CNAME RPZ policy bypass

At a glance

Severity: HIGH 7.5
EPSS: EPSS 0.43 % · percentile 37 (2026-10-27)
State: PUBLISHED
Published: 2026-07-22
Updated: 2026-07-22
Assigner: isc
NVD status: Undergoing Analysis

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.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	isc
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	NVD · security-officer@isc.org (Secondary)

Weaknesses (CWE)

CWE-790

European references

ENISA EUVD · EUVD-2026-47706
GCVE · GCVE-0-2026-11331

CERT-FR advisories

CERTFR-2026-AVI-1376 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr

Affected products

Product	Versions
ISC · BIND 9	affected 9.16.0 ≤ 9.18.50 ; affected 9.20.0 ≤ 9.20.24 ; affected 9.21.0 ≤ 9.21.23 ; affected 9.16.8-S1 ≤ 9.18.50-S1 ; affected 9.20.9-S1 ≤ 9.20.24-S1

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD