CVE-2026-31521
Description
A flaw was found in the Linux kernel. The module loader, specifically in the simplify_symbols() function, does not properly validate the bounds of the ELF (Executable and Linkable Format) section index. An attacker could craft a malicious module with an out-of-bounds st_shndx value, leading to a kernel panic and a Denial of Service (DoS) on the system.
Statement
Upstream bounds-checks st_shndx before indexing sechdrs[], covering corrupted or tool-generated ELF seen in the wild. Red Hat reminds customers that loading unsigned or untrusted kernel modules is outside supported policy; nonetheless the hardening prevents fatal faults. Consume patched kernels; there is no safe unload mitigation for the loader itself.
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 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
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