CVE-2026-31521: Linux kernel · module: Fix kernel panic when a symbol st_shndx is out of bounds
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in f9d69d5e7bde2295eb7488a56f094ac8f5383b92 : patch Linux kernel soon.
Data as of 5 Nov 2026, 22:17 UTC
Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-05.
- Patch
- Available – fixed in f9d69d5e7bde2295eb7488a56f094ac8f5383b92, ef75dc1401d8e797ee51559a0dd0336c225e1776, ec2b22a58073f80739013588af448ff6e2ab906f +4
Exploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
A fix has been implemented in the Linux kernel source to add bounds checking for the st_shndx symbol index in simplify_symbols(). Users should update to a Linux kernel version that includes the commits identified by the fixedVersions hashes. No additional mitigation is indicated.
Description
A vulnerability in the Linux kernel module loader could cause a kernel panic when processing a symbol with an out-of-bounds ELF section index (st_shndx). The issue arises because the module loader does not validate the bounds of st_shndx in simplify_symbols(), leading to a potential fatal exception and system crash. This has been fixed by adding a bounds check to ensure st_shndx is within a valid range before use.
References
- git.kernel.org/stable/c/5d16f519b6eb1d071807e57efe0df2baa8d32ad6 (opens in a new tab)
- git.kernel.org/stable/c/4bbdb0e48176fd281c2b9a211b110db6fd94e175 (opens in a new tab)
- git.kernel.org/stable/c/082f15d2887329e0f43fd3727e69365f5bfe5d2c (opens in a new tab)
- git.kernel.org/stable/c/ec2b22a58073f80739013588af448ff6e2ab906f (opens in a new tab)
- git.kernel.org/stable/c/ef75dc1401d8e797ee51559a0dd0336c225e1776 (opens in a new tab)
- git.kernel.org/stable/c/6ba6957c640f58dc8ef046981a045da43e47ea23 (opens in a new tab)
- git.kernel.org/stable/c/f9d69d5e7bde2295eb7488a56f094ac8f5383b92 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)