CVE-2025-40355: sysfs: check visibility before changing group attribute ownership

mediumCVSS 6.1CVE-2025-40355

CSIRTS triage

vendor: Linux product: Linux kernel Privilege escalation

What: sysfs fails to check attribute visibility before changing group ownership, allowing privilege escalation.
Who is affected: Systems with unprivileged user access to sysfs.
Urgency: Medium priority; local privilege escalation possible via sysfs attribute ownership manipulation.
Action: Update the Linux kernel to check sysfs attribute visibility before modifying ownership.

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

⚡ Watch Linux kernel

Get an email when a new Linux kernel advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 6.1
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-40355

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-2025-403550.18% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 8% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-40355	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] Linux Kernel: Multiple vulnerabilitiescert-bund

Recent advisories for sysfs

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-2026-74552: In the Linux kernel, the following vulnerability has been resolved: hwmon: (lm90) Only report …nvd · 2026-08-15
unknownCVE-2026-74272: In the Linux kernel, the following vulnerability has been resolved: cxl/region: Resolve region…nvd · 2026-08-15
unknownCVE-2026-72176: In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: pu…nvd · 2026-08-15
unknownCVE-2026-72075: In the Linux kernel, the following vulnerability has been resolved: Input: ims-pcu - fix race …nvd · 2026-08-15
highCVE-2026-72066: In the Linux kernel, the following vulnerability has been resolved: cpu: hotplug: Bound hotplu…nvd · 2026-08-15
mediumCVE-2026-68374: usb: core: sysfs: add lock to bos_descriptors_read()msrc · 2026-08-11