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

CSIRTS triage

What

A potential wildcard CNAME RPZ policy bypass vulnerability exists.

Who is affected

Deployments using RPZ policies with wildcard CNAMEs are affected.

Urgency

Remediation is urgent due to the high severity of the vulnerability.

Action

Review and update RPZ policies to mitigate the risk.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source

Microsoft Security Response Center (INTL · vendor-psirt · site)

Severity

high — CVSS 7.5

Published

2026-07-14

Exploitation

Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-11331

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

• Low exploitation riskCVE-2026-113310.42% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 34% of all scored CVEs.

Referenced CVEs

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

• high[NEW] [high] Internet Systems Consortium BIND: Multiple vulnerabilitiescert-bund
• highCVE-2026-11331: An attacker who knows (or guesses) that a resolver uses RPZ with wildcard CNAME policies can c…nvd
• unknownDSA-6395-1 bind9 - security updatedebian

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