CVE-2026-68097 ksmbd: validate ACE size against SID sub-authorities
An attacker can trigger out-of-bounds memory access in the Linux kernel ksmbd module by sending malformed ACEs, potentially leading to code execution or system crash.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68097?
CVE-2026-68097 is a high-severity memory corruption vulnerability in Linux, published on 10 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate ACE size against SID sub-authorities
set_ntacl_dacl() validates sid.num_subauth before copying an ACE, but does not verify that the declared ACE size contains all sub-authorities described by that field. An undersized ACE can therefore be copied and later make the POSIX ACL deduplication walk inspect data beyond the copied ACE boundary.
The existing initial bound check is also too small. It only ensures that the ACE size field is accessible before set_ntacl_dacl() reads sid.num_subauth farther into the input buffer.
Require enough input for the fixed SID header before accessing num_subauth, reject ACEs smaller than that header, and skip ACEs whose declared size cannot contain the complete SID. This makes the validation consistent with the other ACE walk paths.
Which versions are affected by CVE-2026-68097?
How do I fix CVE-2026-68097?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-68097 being exploited?
There is no known exploitation of CVE-2026-68097 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68097, DEBIAN-CVE-2026-68097, GHSA-m2gq-x88q-682f, UBUNTU-CVE-2026-68097.