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Input: touchwin - reset the packet index on every complete packet

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.261, 5.15.212, 6.1.178, 6.12.96, 6.18.39, 6.6.145, 7.1.4
CVEs
CVE-2026-64271
Confirmed fixed CVEs
Not specified
Updated in this feed
7 Nov 2026, 17:52 UTC · Revision 1

Source evidence

Input: touchwin - reset the packet index on every complete packet

core-osv · Original source

Published 25 Jul 2026, 08:49 UTC

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.

osv:CVE-2026-64271

Kernel

Fixed versions: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4

Complete source record
{
  "id": "f67451441f8843568d2bf07f5178280f14bde9e1199e507f1f490a28669d87ca",
  "url": "https://osv.dev/vulnerability/CVE-2026-64271",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Input: touchwin - reset the packet index on every complete packet",
    "summary": "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.",
    "evidence": "osv:CVE-2026-64271",
    "products": [
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        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.261",
            "evidence": "/affected/1/ranges"
          },
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            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
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            "evidence": "/affected/1/ranges"
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          {
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            "evidence": "/affected/1/ranges"
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          {
            "value": "6.18.39",
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          },
          {
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            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-64271",
      "aliases": [
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      "affected": [
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                {
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                  "introduced": "2.6.19"
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              "type": "ECOSYSTEM",
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                  "introduced": "5.11.0"
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            {
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
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        }
      ],
      "modified": "2026-10-28T02:30:51.307715777Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/044167cba2384bcd783547ad5e30ecd292b30919",
        "https://git.kernel.org/stable/c/3e6f007b43e2fc6546e21fa74ee62c38984a6672",
        "https://git.kernel.org/stable/c/431ad239f2924dff337c3fccb9246597c1b63185",
        "https://git.kernel.org/stable/c/478cdd736f2ce3114f90e775d7358136d3977b94",
        "https://git.kernel.org/stable/c/6c9f29f128dd4057404838259af4c645318487e1",
        "https://git.kernel.org/stable/c/70e4248793762df9832fd4fc2fc6ac7924572c36",
        "https://git.kernel.org/stable/c/a8d87184576c889759e3aab899799a482f1e1a5b",
        "https://git.kernel.org/stable/c/ed9b66905407eb3d02df1aaeed82eb7a7f0eb508",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64271.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64271",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64271.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64271",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 520021,
  "published_at": "2026-07-25T08:49:18.16+00:00"
}