What’s Vulnerable › Vulnerabilities

CVE-2025-68786: ksmbd: skip lock-range check on equal size to avoid size==0 underflow

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-13 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: skip lock-range check on equal size to avoid size==0 underflow When size equals the current i_size (including 0), the code used to call check_lock_range(filp, i_size, size - 1, WRITE), which computes `size - 1` and can underflow for size==0. Skip the equal case.

Affected products

• Linux kernel: 5.15 — fixed in 6.19

How to fix

Upgrade to a fixed version: Linux kernel 6.19. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/52fcbb92e0d3acfd1448b2a43b6595d540da5295
• https://git.kernel.org/stable/c/571204e4758a528fbd67330bd4b0dfbdafb33dd8
• https://git.kernel.org/stable/c/5d510ac31626ed157d2182149559430350cf2104
• https://git.kernel.org/stable/c/a6f4cfa3783804336491e0edcb250c25f9b59d33
• https://git.kernel.org/stable/c/da29cd197246c85c0473259f1cad897d9d28faea

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