CVE-2026-68100: ksmbd: validate num_subauth when copying ACE in set_ntacl_dacl

CSIRTS triage

What

The ksmbd set_ntacl_dacl function does not validate num_subauth when copying ACE entries, causing potential buffer overflow.

Who is affected

Linux systems running ksmbd SMB server with ACL operations.

Urgency

Medium priority; not exploited but memory corruption in ACL handling poses risk.

Action

Apply kernel patch adding num_subauth validation in set_ntacl_dacl.

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 4.3

Published

2026-08-11

Exploitation

Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68100

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-2026-681000.40% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 34% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

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

• high[NEW] [high] Linux Kernel: Multiple vulnerabilitiescert-bund
• highCVE-2026-68100: In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate num_subaut…nvd

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