CyberSecBulletin
CVE-2025-38198NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2025-38198 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 b3237d451bf3a4490cb1a76f3b7c91d9888f1c4b, 519ba75728ee8cd561dce25fc52a2ec5c47171dc, f28f1f578cd810779d01999c60618cda14c281dd 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 0.19% 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 b3237d451bf3a4490cb1a76f3b7c91d9888f1c4b or 519ba75728ee8cd561dce25fc52a2ec5c47171dc or f28f1f578cd810779d01999c60618cda14c281dd or 54b28f7c567dd659e5f9562f518e4d7f3f6a367b, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.142 or 6.6.95 or 6.12.35 or 6.15.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux409d6c95f9c68bb7046410a3502e26e454a1e636 up to, but not including, b3237d451bf3a4490cb1a76f3b7c91d9888f1c4b; 409d6c95f9c68bb7046410a3502e26e454a1e636 up to, but not including, 519ba75728ee8cd561dce25fc52a2ec5c47171dc; 409d6c95f9c68bb7046410a3502e26e454a1e636 up to, but not including, f28f1f578cd810779d01999c60618cda14c281dd; 409d6c95f9c68bb7046410a3502e26e454a1e636 up to, but not including, 54b28f7c567dd659e5f9562f518e4d7f3f6a367b; 409d6c95f9c68bb7046410a3502e26e454a1e636 up to, but not including, cedc1b63394a866bf8663a3e40f4546f1d28c8d8; 5.19b3237d451bf3a4490cb1a76f3b7c91d9888f1c4b, 519ba75728ee8cd561dce25fc52a2ec5c47171dc, f28f1f578cd810779d01999c60618cda14c281dd, 54b28f7c567dd659e5f9562f518e4d7f3f6a367b, cedc1b63394a866bf8663a3e40f4546f1d28c8d8
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
LinuxLinux Kernelbefore 6.1.142; 6.2 up to, but not including, 6.6.95; 6.7 up to, but not including, 6.12.35; 6.13 up to, but not including, 6.15.46.1.142, 6.6.95, 6.12.35, 6.15.4
DebianDebian Linux11.0Not stated

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: fbcon: Make sure modelist not set on unregistered console It looks like attempting to write to the "store_modes" sysfs node will run afoul of unregistered consoles: UBSAN: array-index-out-of-bounds in drivers/video/fbdev/core/fbcon.c:122:28 index -1 is out of range for type 'fb_info *[32]' ... fbcon_info_from_console+0x192/0x1a0 drivers/video/fbdev/core/fbcon.c:122 fbcon_new_modelist+0xbf/0x2d0 drivers/video/fbdev/core/fbcon.c:3048 fb_new_modelist+0x328/0x440 drivers/video/fbdev/core/fbmem.c:673 store_modes+0x1c9/0x3e0 drivers/video/fbdev/core/fbsysfs.c:113 dev_attr_store+0x55/0x80 drivers/base/core.c:2439 static struct fb_info *fbcon_registered_fb[FB_MAX]; ... static signed char con2fb_map[MAX_NR_CONSOLES]; ... static struct fb_info *fbcon_info_from_console(int console) ... return fbcon_registered_fb[con2fb_map[console]]; If con2fb_map contains a -1 things go wrong here. Instead, return NULL, as callers of fbcon_info_from_console() are trying to compare against existing "info" pointers, so error handling should kick in correctly.

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

Third-party and government advisories

Recent Improper Validation of Array Index vulnerabilities

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