CVE-2026-34180: Heap Buffer Over-read in ASN.1 Content Parsing

highCVSS 7.5CVE-2026-34180

CSIRTS triage

vendor: null product: nullOther

What: A heap buffer over-read can occur in ASN.1 content parsing.
Who is affected: Systems that parse ASN.1 content.
Urgency: Remediation is urgent due to the high severity and potential for information leakage.
Action: Patch the ASN.1 parsing implementation to prevent buffer over-reads.

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: high — CVSS 7.5
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34180

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-2026-341800.51% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 40% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-34180	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

high[UPDATE] [high] OpenSSL: Multiple Vulnerabilitiescert-bund
unknownMultiple vulnerabilities in Tenable Identity Exposure (June 24, 2026)cert-fr-avis

Recent advisories for Heap Buffer Over-read

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.

mediumCVE-2025-15661: libssh2 - Heap Buffer Over-read via sftp_symlink() in sftp.cmsrc · 2026-06-09