CVE-2026-64324: udf: validate free block extents against the partition length

mediumCVSS 5.5CVE-2026-64324

CSIRTS triage

Other

What: Free block extents are validated against the partition length.
Who is affected: Deployments using the UDF filesystem.
Urgency: Remediation is recommended to prevent potential filesystem issues, with no current exploitation.
Action: Update to the patched version once released.

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

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.5
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64324

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-2026-643240.16% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64324	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

highCVE-2026-64324: In the Linux kernel, the following vulnerability has been resolved: udf: validate free block e…nvd

Recent advisories for udf

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.

highCVE-2026-64324: In the Linux kernel, the following vulnerability has been resolved: udf: validate free block e…nvd · 2026-07-25
highCVE-2026-64323: In the Linux kernel, the following vulnerability has been resolved: udf: validate VAT header l…nvd · 2026-07-25
highCVE-2026-64322: In the Linux kernel, the following vulnerability has been resolved: udf: validate sparing tabl…nvd · 2026-07-25
highCVE-2026-53369: In the Linux kernel, the following vulnerability has been resolved: udf: reject descriptors wi…nvd · 2026-07-19
highCVE-2026-62350: TDengine is an open source, time-series database optimized for Internet of Things devices. Pri…nvd · 2026-07-15
highCVE-2026-50498: Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerabilitynvd · 2026-07-14