{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-31696",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-31696"
  ],
  "published": "2026-05-01T13:56:32Z",
  "summary": "rxrpc: Fix missing validation of ticket length in non-XDR key preparsing",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix missing validation of ticket length in non-XDR key preparsing\n\nIn rxrpc_preparse(), there are two paths for parsing key payloads: the\nXDR path (for large payloads) and the non-XDR path (for payloads <= 28\nbytes). While the XDR path (rxrpc_preparse_xdr_rxkad()) correctly\nvalidates the ticket length against AFSTOKEN_RK_TIX_MAX, the non-XDR\npath fails to do so.\n\nThis allows an unprivileged user to provide a very large ticket length.\nWhen this key is later read via rxrpc_read(), the total\ntoken size (toksize) calculation results in a value that exceeds\nAFSTOKEN_LENGTH_MAX, triggering a WARN_ON().\n\n[ 2001.302904] WARNING: CPU: 2 PID: 2108 at net/rxrpc/key.c:778 rxrpc_read+0x109/0x5c0 [rxrpc]\n\nFix this by adding a check in the non-XDR parsing path of rxrpc_preparse()\nto ensure the ticket length does not exceed AFSTOKEN_RK_TIX_MAX,\nbringing it into parity with the XDR parsing logic.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.175",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31696"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/44714dfda386884919ba366411880b6fb3c3efd3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/41a117dd80371343babc52198d1114e83eb37627"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9a397aa9b5e53ca63d4d6aefb542832eca389618"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1fa36cf495b0023e8475d038535c05e4063211e1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4458757c020592a3094366e0fb20457383b42f92"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ce383ba615339f8eaec646a166d2c2b015bb5ca0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a1be1c9ece26cea69654f28b255ff9a7906b897b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ac33733b10b484d666f97688561670afd5861383"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-06-15T02:03:26Z"
  }
}