CyberSecBulletin
CVE-2025-71203NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2025-71203 is a high-severity improper validation of array index vulnerability in Linux, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 33743ec6679aa364ee19d1afbaa50593e9e6e443, c45848936ebdb4fcab92f8c39510db83c16d0239, 8b44e753795107a22ba31495686e83f4aca48f36 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.15% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 33743ec6679aa364ee19d1afbaa50593e9e6e443 or c45848936ebdb4fcab92f8c39510db83c16d0239 or 8b44e753795107a22ba31495686e83f4aca48f36 or 25fd7ee7bf58ac3ec7be3c9f82ceff153451946c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.12.70 or 6.18.10, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxf0bddf50586da81360627a772be0e355b62f071e up to, but not including, 33743ec6679aa364ee19d1afbaa50593e9e6e443; f0bddf50586da81360627a772be0e355b62f071e up to, but not including, c45848936ebdb4fcab92f8c39510db83c16d0239; f0bddf50586da81360627a772be0e355b62f071e up to, but not including, 8b44e753795107a22ba31495686e83f4aca48f36; f0bddf50586da81360627a772be0e355b62f071e up to, but not including, 25fd7ee7bf58ac3ec7be3c9f82ceff153451946c; 6.433743ec6679aa364ee19d1afbaa50593e9e6e443, c45848936ebdb4fcab92f8c39510db83c16d0239, 8b44e753795107a22ba31495686e83f4aca48f36, 25fd7ee7bf58ac3ec7be3c9f82ceff153451946c
LinuxLinux Kernel6.4 up to, but not including, 6.12.70; 6.13 up to, but not including, 6.18.10; 6.196.12.70, 6.18.10

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: riscv: Sanitize syscall table indexing under speculation The syscall number is a user-controlled value used to index into the syscall table. Use array_index_nospec() to clamp this value after the bounds check to prevent speculative out-of-bounds access and subsequent data leakage via cache side channels.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

How developers prevent this class of flaw

  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.

More Improper Validation of Array Index vulnerabilities (CWE-129)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Improper Validation of Array Index vulnerabilities

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