CVE-2026-31521

Kernel panic via unchecked ELF section index

Published Apr 22, 2026 · Updated Apr 22, 2026

Out-of-bounds access in the Linux kernel module loader allows local users to trigger a kernel panic via a malformed module ELF file. simplify_symbols() uses each symbol's st_shndx value to index info->sechdrs without first checking that the section index is in range. Access capable of loading a corrupted or SHN_XINDEX-using kernel module is required; the reported consequence is a fatal page fault and system crash.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in the Linux kernel module loader allows local users to trigger a kernel panic via a malformed module ELF file. simplify_symbols() uses each symbol's st_shndx value to index info->sechdrs without first checking that the section index is in range. Access capable of loading a corrupted or SHN_XINDEX-using kernel module is required; the reported consequence is a fatal page fault and system crash.

The record

CVE
CVE-2026-31521
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-787, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <082f15d2887329e0f43fd3727e69365f5bfe5d2c
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4bbdb0e48176fd281c2b9a211b110db6fd94e175
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5d16f519b6eb1d071807e57efe0df2baa8d32ad6
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6ba6957c640f58dc8ef046981a045da43e47ea23
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ec2b22a58073f80739013588af448ff6e2ab906f
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef75dc1401d8e797ee51559a0dd0336c225e1776
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f9d69d5e7bde2295eb7488a56f094ac8f5383b92

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <082f15d2887329e0f43fd3727e69365f5bfe5d2c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4bbdb0e48176fd281c2b9a211b110db6fd94e175; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5d16f519b6eb1d071807e57efe0df2baa8d32ad6; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6ba6957c640f58dc8ef046981a045da43e47ea23; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ec2b22a58073f80739013588af448ff6e2ab906f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef75dc1401d8e797ee51559a0dd0336c225e1776; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f9d69d5e7bde2295eb7488a56f094ac8f5383b92

Published CVSS scores

5.5GitHub Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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