Improper Validation of Array Index Affecting linux-6.12 package, versions <6.12.100-1~deb12u1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.17% (7th percentile)

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  • Snyk IDSNYK-ECHOLATEST-LINUX612-18579141
  • published7 Aug 2026
  • disclosed25 Jul 2026

Introduced: 25 Jul 2026

CVE-2026-64271  (opens in a new tab)
CWE-129  (opens in a new tab)

How to fix?

Upgrade Echo:latest linux-6.12 to version 6.12.100-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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-&gt;data[tw-&gt;idx++] = data;
if (tw-&gt;idx == TW_LENGTH &amp;&amp; tw-&gt;data[1] == tw-&gt;data[2]) {
    ...
    tw-&gt;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.

CVSS Base Scores

version 3.1