CVE-2026-11721: Cache poisoning possible with label count discrepancy, RRSIG, and wildcards

highCVSS 7.5CVE-2026-11721

CSIRTS triage

Other

What: Cache poisoning is possible due to a label count discrepancy, RRSIG, and wildcards.
Who is affected: Systems relying on DNS caching are affected.
Urgency: Remediation is urgent due to the high severity of the vulnerability.
Action: Implement measures to validate DNS responses to prevent cache poisoning.

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-2026-11721

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-2026-117210.39% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 31% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-11721	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

Recent advisories for Cache poisoning possible

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-50252: Possible cache poisoning attack by mapping source port population per threadmsrc · 2026-07-14