Linux Kernel up to 6.19.10 simplify_symbols st_shndx out-of-bounds

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CTI Interest Score
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4.4$0-$5k0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.19.10. Affected by this issue is the function simplify_symbols. Such manipulation of the argument st_shndx leads to out-of-bounds. This vulnerability is listed as CVE-2026-31521. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.19.10 and classified as problematic. Affected by this issue is the function simplify_symbols. The manipulation of the argument st_shndx with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: module: Fix kernel panic when a symbol st_shndx is out of bounds The module loader doesn't check for bounds of the ELF section index in simplify_symbols(): for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) { const char *name = info->strtab + sym[i].st_name; switch (sym[i].st_shndx) { case SHN_COMMON: [...] default: /* Divert to percpu allocation if a percpu var. */ if (sym[i].st_shndx == info->index.pcpu) secbase = (unsigned long)mod_percpu(mod); else /** HERE --> **/ secbase = info->sechdrs[sym[i].st_shndx].sh_addr; sym[i].st_value += secbase; break; } } A symbol with an out-of-bounds st_shndx value, for example 0xffff (known as SHN_XINDEX or SHN_HIRESERVE), may cause a kernel panic: BUG: unable to handle page fault for address: ... RIP: 0010:simplify_symbols+0x2b2/0x480 ... Kernel panic - not syncing: Fatal exception This can happen when module ELF is legitimately using SHN_XINDEX or when it is corrupted. Add a bounds check in simplify_symbols() to validate that st_shndx is within the valid range before using it. This issue was discovered due to a bug in llvm-objcopy, see relevant discussion for details [1]. [1] https://lore.kernel.org/linux-modules/[email protected]/

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-31521 since 03/09/2026. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 316948 (Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1746)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.203, 6.1.168, 6.6.131, 6.12.80, 6.18.21 or 6.19.11 eliminates this vulnerability. Applying the patch 5d16f519b6eb1d071807e57efe0df2baa8d32ad6/4bbdb0e48176fd281c2b9a211b110db6fd94e175/082f15d2887329e0f43fd3727e69365f5bfe5d2c/ec2b22a58073f80739013588af448ff6e2ab906f/ef75dc1401d8e797ee51559a0dd0336c225e1776/6ba6957c640f58dc8ef046981a045da43e47ea23/f9d69d5e7bde2295eb7488a56f094ac8f5383b92 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (316948) and CERT Bund (WID-SEC-2026-1252). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • Siemens SIMATIC S7
  • Proxmox Virtual Environment

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.5
VulDB Meta Temp Score: 4.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 316948
Nessus Name: Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1746)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.203/6.1.168/6.6.131/6.12.80/6.18.21/6.19.11
Patch: 5d16f519b6eb1d071807e57efe0df2baa8d32ad6/4bbdb0e48176fd281c2b9a211b110db6fd94e175/082f15d2887329e0f43fd3727e69365f5bfe5d2c/ec2b22a58073f80739013588af448ff6e2ab906f/ef75dc1401d8e797ee51559a0dd0336c225e1776/6ba6957c640f58dc8ef046981a045da43e47ea23/f9d69d5e7bde2295eb7488a56f094ac8f5383b92

Timelineinfo

03/09/2026 CVE reserved
04/22/2026 +43 days Advisory disclosed
04/22/2026 +0 days VulDB entry created
07/26/2026 +95 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31521 (🔒)
GCVE (CVE): GCVE-0-2026-31521
GCVE (VulDB): GCVE-100-358898
CERT Bund: WID-SEC-2026-1252 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/22/2026 17:11
Updated: 07/26/2026 08:16
Changes: 04/22/2026 17:11 (59), 05/28/2026 00:17 (2), 06/18/2026 08:59 (7), 07/17/2026 05:31 (12), 07/26/2026 08:16 (3)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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