CVE-2026-7531: Use-after-free in PQC hybrid key-share handling

criticalCVSS 9.8CVE-2026-7531

CSIRTS triage

Other

What: Use-after-free vulnerability in PQC hybrid key-share handling.
Who is affected: Deployments using the affected PQC hybrid key-share handling are at risk.
Urgency: Remediation is critical due to the high severity of the vulnerability.
Action: Update to the patched version as soon as it is available.

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

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: critical — CVSS 9.8
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-7531

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-2026-75310.35% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 27% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-7531	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

criticalCVE-2026-7531: Use-after-free in PQC hybrid key-share handling. This is an incomplete-fix follow-up to CVE-202…nvd

Recent advisories for Use-after-free in PQC

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.

criticalCVE-2026-7531: Use-after-free in PQC hybrid key-share handling. This is an incomplete-fix follow-up to CVE-202…nvd · 2026-06-25