What’s Vulnerable › Vulnerabilities

CVE-2026-64138: ksmbd: validate SID in parent security descriptor during ACL inheritance

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-19 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate SID in parent security descriptor during ACL inheritance Introduce smb_validate_ntsd_sid() helper to safely validate Owner SID and Group SID inside the NT Security Descriptor (smb_ntsd) retrieved from the parent directory.

Affected products

• Linux kernel: from 5.15 before 6.12.92; from 6.13 before 6.18.34; from 6.19 before 7.0.11; 7.1-rc1, 7.1-rc2, 7.1-rc3, 7.1-rc4 — fixed in 6.12.92, 6.18.34, 7.0.11
• Linux: 5.15 — fixed in 7.1

How to fix

Upgrade to a fixed version: Linux kernel 6.12.92, 6.18.34, 7.0.11; Linux 7.1. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/18d8db24b0a5b7be4829238dd4022236df02d421
• https://git.kernel.org/stable/c/1c9d0646a9959752f11ca1080dc1ff26bd1756cb
• https://git.kernel.org/stable/c/69f030cf95488ae1186c72ac8c66fd279664ea7f
• https://git.kernel.org/stable/c/8efbea0253b7fa2d1960cab0fed36544ca0b41ab
• https://git.kernel.org/stable/c/f0e5c9c663badc9982e6941322eef1cb17de0f11
• https://git.kernel.org/stable/c/f7c4dee323d9176b8d3f5c69018ee57ae0d4653c

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