CVE-2026-56416: Possible heap buffer overflow when validator canonicalizes RDATA that contains domain name

mediumCVSS 4.8CVE-2026-56416

CSIRTS triage

vendor: null product: nullOther

What: Possible heap buffer overflow when validator canonicalizes RDATA containing a domain name.
Who is affected: Systems processing DNS data are affected.
Urgency: Remediation is medium urgency due to potential exploitation risks.
Action: Update DNS processing libraries to mitigate the risk.

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

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 4.8
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56416

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-2026-564160.12% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 2% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-56416	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 Possible heap buffer

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