CVE-2026-68099
Description
A flaw was found in ksmbd, a Linux kernel module that provides an in-kernel SMB server. An integer overflow vulnerability exists when processing Access Control Lists (ACLs). This flaw can lead to a malformed ACL, which, when re-parsed by clients or ksmbd itself, may trigger out-of-bounds reads. This could potentially allow an attacker to gain access to sensitive information.
Statement
This flaw in the ksmbd kernel module can lead to out-of-bounds reads when processing specially crafted Access Control Lists (ACLs). An attacker with local access could exploit this vulnerability to cause a denial of service or potentially disclose sensitive information on affected Red Hat Enterprise Linux systems where ksmbd is actively used.
Mitigation
To prevent the `ksmbd` kernel module from loading, create a modprobe configuration file.
1. Create `/etc/modprobe.d/disable-ksmbd.conf` with:
install ksmbd /bin/true2. Regenerate the initramfs:
blacklist ksmbd
bash3. Reboot the system for the changes to take effect.
dracut -f -v
bashDisabling `ksmbd` will impact SMB server functionality provided by the kernel module.
reboot
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 | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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