CVE-2026-43112
Description
A flaw was found in the Linux kernel's CIFS (Common Internet File System) client. When the cifs_sanitize_prepath function processes specially crafted input, such as an empty string or a string containing only delimiters, it can attempt to read data beyond its allocated memory buffer. This out-of-bounds read can lead to a system crash, resulting in a denial of service.
Statement
An Important out-of-bounds read flaw in the Linux kernel's CIFS client can lead to a system crash and denial of service. This vulnerability, present in Red Hat Enterprise Linux 8, 9, and 10, and Red Hat In-Vehicle OS 2, can be triggered by processing specially crafted input to the cifs_sanitize_prepath function, potentially disrupting system availability.
Mitigation
To mitigate this issue, prevent the `cifs` kernel module from loading if CIFS client functionality is not required. This can be achieved by blacklisting the module.
Create a file named `/etc/modprobe.d/blacklist-cifs.conf` with the following content:
blacklist cifsAfter creating the file, regenerate the initramfs and reboot the system for the changes to take effect.
bashDisabling the `cifs` module will prevent the system from mounting CIFS network shares, which may impact functionality relying on this protocol.
dracut -f -v
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.1 | N/A | 8.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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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