CyberSecBulletin
CVE-2026-64271NVD status: Analyzed

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2026-64271 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 ed9b66905407eb3d02df1aaeed82eb7a7f0eb508, 044167cba2384bcd783547ad5e30ecd292b30919, 6c9f29f128dd4057404838259af4c645318487e1 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 0.17% 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 ed9b66905407eb3d02df1aaeed82eb7a7f0eb508 or 044167cba2384bcd783547ad5e30ecd292b30919 or 6c9f29f128dd4057404838259af4c645318487e1 or 431ad239f2924dff337c3fccb9246597c1b63185, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, ed9b66905407eb3d02df1aaeed82eb7a7f0eb508; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, 044167cba2384bcd783547ad5e30ecd292b30919; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, 6c9f29f128dd4057404838259af4c645318487e1; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, 431ad239f2924dff337c3fccb9246597c1b63185; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, 70e4248793762df9832fd4fc2fc6ac7924572c36; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, 3e6f007b43e2fc6546e21fa74ee62c38984a6672; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, a8d87184576c889759e3aab899799a482f1e1a5b; 11ea3173d5f2de71d037ef58ac43395795fed2bc up to, but not including, 478cdd736f2ce3114f90e775d7358136d3977b94; and 1 more rangesed9b66905407eb3d02df1aaeed82eb7a7f0eb508, 044167cba2384bcd783547ad5e30ecd292b30919, 6c9f29f128dd4057404838259af4c645318487e1, 431ad239f2924dff337c3fccb9246597c1b63185, 70e4248793762df9832fd4fc2fc6ac7924572c36, 3e6f007b43e2fc6546e21fa74ee62c38984a6672
LinuxLinux Kernel2.6.19 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.45.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39

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: Input: touchwin - reset the packet index on every complete packet tw_interrupt() accumulates each non-zero serial byte into a fixed three-byte buffer with a running index that is only reset once a full packet has been received *and* the device's two Y bytes agree: tw->data[tw->idx++] = data; if (tw->idx == TW_LENGTH && tw->data[1] == tw->data[2]) { ... tw->idx = 0; } The reset is gated on tw->data[1] == tw->data[2], a value the device controls. A malicious, malfunctioning or counterfeit Touchwindow peripheral can stream non-zero bytes whose 2nd and 3rd bytes differ: the index reaches TW_LENGTH without the equality holding, is never reset, and keeps growing, so tw->data[tw->idx++] walks off the end of the three-byte array and the rest of the heap-allocated struct tw, one attacker-chosen byte at a time -- an unbounded, device-driven heap out-of-bounds write. Reset the index on every completed packet and report an event only when the two Y bytes match, like the other serio touchscreen drivers do.

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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