CVE-2026-17523
Description
A flaw was found in the Linux kernel in net/can/bcm.c in can: bcm, where an unprivileged local user can exploit this vulnerability to execute arbitrary code within the kernel, which leads to a local privilege escalation (LPE). This allows the attacker to gain root privileges and take full control of the affected system.
Statement
This is an Important flaw in the Linux kernel's CAN BCM module that allows a local unprivileged attacker to achieve root privileges through arbitrary kernel code execution. The vulnerability is present in Red Hat Enterprise Linux 8, where a proof of concept has demonstrated local privilege escalation, even without unprivileged user namespaces or the kernel-modules-extra package.
Mitigation
To mitigate this vulnerability, prevent the `bcm` kernel module from loading if it is not required. Create a file named `/etc/modprobe.d/blacklist-bcm.conf` with the content `blacklist bcm`. A system reboot is required for this change to take effect. This mitigation may impact functionality that relies on the CAN BCM module.
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 | 7.8 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| 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 | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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