CyberSecBulletin
CVE-2024-38631NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2024-38631 is a high-severity improper validation of array index vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 8dbcb3a8cfdf8ff5afce62dad50790278ff0d3b7, 51fafb3cd7fcf4f4682693b4d2883e2a5bfffe33 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 0.21% 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 8dbcb3a8cfdf8ff5afce62dad50790278ff0d3b7 or 51fafb3cd7fcf4f4682693b4d2883e2a5bfffe33, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.9.4 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux0fb528c8255bd2de6a2fba26ed28d75a7f0cb630 up to, but not including, 8dbcb3a8cfdf8ff5afce62dad50790278ff0d3b7; 0fb528c8255bd2de6a2fba26ed28d75a7f0cb630 up to, but not including, 51fafb3cd7fcf4f4682693b4d2883e2a5bfffe33; 6.98dbcb3a8cfdf8ff5afce62dad50790278ff0d3b7, 51fafb3cd7fcf4f4682693b4d2883e2a5bfffe33
LinuxLinux Kernel6.9 up to, but not including, 6.9.46.9.4

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
LowNo special conditions are needed; the attack works reliably.
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:L/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: iio: adc: PAC1934: fix accessing out of bounds array index Fix accessing out of bounds array index for average current and voltage measurements. The device itself has only 4 channels, but in sysfs there are "fake" channels for the average voltages and currents too.

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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Validation of Array Index vulnerabilities

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