CyberSecBulletin
CVE-2026-23448NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2026-23448 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 63c35b8fce77a7892e8fa06c540d4943145506eb, f1c7701d3ac91b62d672c13690cf295821f0d5c3, 789204f980730258c983102c027c375238009c80 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 0.13% 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 63c35b8fce77a7892e8fa06c540d4943145506eb or f1c7701d3ac91b62d672c13690cf295821f0d5c3 or 789204f980730258c983102c027c375238009c80 or 403f94ddcb36c552fbef51dea735b131e3dcde8b, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.130 or 6.12.78 or 6.18.20 or 6.19.10, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxff06ab13a4ccae4acb44a2d4e3ece367b616ab50 up to, but not including, 63c35b8fce77a7892e8fa06c540d4943145506eb; ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 up to, but not including, f1c7701d3ac91b62d672c13690cf295821f0d5c3; ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 up to, but not including, 789204f980730258c983102c027c375238009c80; ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 up to, but not including, 403f94ddcb36c552fbef51dea735b131e3dcde8b; ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 up to, but not including, dce9dda0e3707e887977db44407989e9ead26611; ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 up to, but not including, 2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a; 3.863c35b8fce77a7892e8fa06c540d4943145506eb, f1c7701d3ac91b62d672c13690cf295821f0d5c3, 789204f980730258c983102c027c375238009c80, 403f94ddcb36c552fbef51dea735b131e3dcde8b, dce9dda0e3707e887977db44407989e9ead26611, 2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a
LinuxLinux Kernel3.8 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.20; 6.19 up to, but not including, 6.19.10; 7.06.6.130, 6.12.78, 6.18.20, 6.19.10

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
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: net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check cdc_ncm_rx_verify_ndp16() validates that the NDP header and its DPE entries fit within the skb. The first check correctly accounts for ndpoffset: if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) but the second check omits it: if ((sizeof(struct usb_cdc_ncm_ndp16) + ret * (sizeof(struct usb_cdc_ncm_dpe16))) > skb_in->len) This validates the DPE array size against the total skb length as if the NDP were at offset 0, rather than at ndpoffset. When the NDP is placed near the end of the NTB (large wNdpIndex), the DPE entries can extend past the skb data buffer even though the check passes. cdc_ncm_rx_fixup() then reads out-of-bounds memory when iterating the DPE array. Add ndpoffset to the nframes bounds check and use struct_size_t() to express the NDP-plus-DPE-array size more clearly.

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

Spotted an error? Tell us.