CyberSecBulletin
CVE-2026-64460NVD status: Analyzed

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2026-64460 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 b77524621250407386f44c6eea7e5e4619ada1ce, 55fd485e66d0ad5c762c23dba1461fe9c741cd96, f34f1712229d71ce4286440fef12526fd4590b37 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 0.14% 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 b77524621250407386f44c6eea7e5e4619ada1ce or 55fd485e66d0ad5c762c23dba1461fe9c741cd96 or f34f1712229d71ce4286440fef12526fd4590b37, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.39 or 7.1.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux5a8f77e24a30bbce2fa57926f3dede84894fd10a up to, but not including, b77524621250407386f44c6eea7e5e4619ada1ce; 5a8f77e24a30bbce2fa57926f3dede84894fd10a up to, but not including, 55fd485e66d0ad5c762c23dba1461fe9c741cd96; 5a8f77e24a30bbce2fa57926f3dede84894fd10a up to, but not including, f34f1712229d71ce4286440fef12526fd4590b37; 6.17b77524621250407386f44c6eea7e5e4619ada1ce, 55fd485e66d0ad5c762c23dba1461fe9c741cd96, f34f1712229d71ce4286440fef12526fd4590b37
LinuxLinux Kernel6.17 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.46.18.39, 7.1.4

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
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
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
LowSome restricted data can be read.
Integrity
LowLimited modification of data is possible.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: PCI/IOV: Skip VF Resizable BAR restore on read error sriov_restore_vf_rebar_state() uses the VF Resizable BAR Control register to decide how many VF BARs to restore (nbars) and which VF BAR each iteration addresses (bar_idx). bar_idx indexes into dev->sriov->barsz[], which has only PCI_SRIOV_NUM_BARS (6) entries. When a device does not respond, config reads typically return PCI_ERROR_RESPONSE (~0). Both fields are 3 bits wide, so nbars and bar_idx both evaluate to 7. The barsz[] access then goes out of bounds. UBSAN reports this as: UBSAN: array-index-out-of-bounds in drivers/pci/iov.c:948:51 index 7 is out of range for type 'resource_size_t [6]' Observed on an NVIDIA RTX PRO 1000 GPU (GB207GLM) that stopped responding during a failed GC6 power state exit. The subsequent pci_restore_state() invoked sriov_restore_vf_rebar_state() while config reads returned 0xffffffff, triggering the splat. Bail out if any VF Resizable BAR Control read returns PCI_ERROR_RESPONSE. No further VF BARs are touched, which is safe because a config read that returns PCI_ERROR_RESPONSE indicates the device is unreachable and restoration is pointless. This mirrors the guard in pci_restore_rebar_state().

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.