CVE-2026-31507
Description
A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SMC) module. A local user can exploit this vulnerability by using the tee(2) system call to duplicate a splice pipe buffer, leading to a double-free condition. This double-free can result in a use-after-free error and a kernel null pointer dereference, ultimately causing a kernel panic and a denial of service on the affected system.
Statement
Upstream rejects tee()/splice_pipe_to_pipe() paths that would duplicate SMC pipe buffers because refcounting alone cannot fix receive-window accounting. Red Hat advises patched kernels for SMC users. Unload smc where the protocol is unused.
Mitigation
To mitigate this issue, prevent the smc module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
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 | 5.5 | 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 | None | N/A | High |
| Integrity Impact | None | 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:N/I:N/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)
Availability
Technical Impact: DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An adversary that can cause a resource counter to become inaccurate may be able to create situations where resources are not accounted for and not released, thus causing resources to become scarce for future needs.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An adversary that can cause a resource counter to become inaccurate may be able to force an error that causes the product to crash or exit out of its current operation.
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