CVE-2026-68381
Description
A flaw was found in ksmbd, a Linux kernel module that provides an in-kernel SMB server. A race condition exists during connection teardown and asynchronous oplock or lease break notifications. This can lead to a use-after-free vulnerability, where a freed connection object is still accessed by a queued worker. This issue could potentially result in memory corruption, leading to system instability or a denial of service.
Statement
Red Hat Enterprise Linux is not impacted by this vulnerability because the ksmbd module is unsupported and disabled by default.
Mitigation
To mitigate this vulnerability, prevent the ksmbd kernel module from loading if its functionality is not required. Create a file /etc/modprobe.d/disable-ksmbd.conf with the content `blacklist ksmbd`. Regenerate the initramfs using `dracut -f -v` and reboot the system for the changes to take effect. Disabling ksmbd will prevent the system from serving SMB shares.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7 | N/A | 9.8 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Modify Application Data; Modify Memory; DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands
It may be possible to cause data corruption and possibly execute arbitrary code by modifying global variables or data structures at unexpected times, violating the assumptions of code that uses this global data.
Access Control
Technical Impact: Gain Privileges or Assume Identity
If a signal handler interrupts code that is executing with privileges, it may be possible that the signal handler will also be executed with elevated privileges, possibly making subsequent exploits more severe.
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