SB20260812140 - Use-after-free in Linux kernel smb server
Published: August 12, 2026
Security Bulletin ID
SB20260812140
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-68381)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to a use-after-free in async oplock and lease break notification handling in fs/smb/server/oplock.c when processing asynchronous oplock break notifications during connection teardown. A remote user can trigger a race condition to cause a denial of service.
Exploitation requires a race between connection teardown and an oplock or lease break notification.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/stable/c/0f72fc9659d7f585460d43c158055df5afdcffb6
- https://git.kernel.org/stable/c/14062c74e5b25c27edcff7a2fe0dc701c930b372
- https://git.kernel.org/stable/c/6ecb252efa0b413ac3d9979fb4eec247f8fc1258
- https://git.kernel.org/stable/c/793e1c7041b93af96ff87e678329bc16aee7ba88
- https://git.kernel.org/stable/c/aa5d8f3f96aa11a4a54ce993c11ce8af11c546f9