{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-68278",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-68278"
  ],
  "published": "2026-08-10T12:08:00Z",
  "summary": "drm/dp/mst: fix buffer overflows in sideband chunk accumulation",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/dp/mst: fix buffer overflows in sideband chunk accumulation\n\ndrm_dp_sideband_append_payload() has three related bugs when processing\ndevice-provided sideband reply data:\n\n1. Zero-length curchunk_len underflow: msg_len is a 6-bit field taken\n   directly from the DP sideband header. If a device sends msg_len=0,\n   curchunk_len is set to zero. The condition (curchunk_idx >= curchunk_len)\n   is immediately true, and curchunk_len-1 wraps to 255 (u8 underflow).\n   drm_dp_msg_data_crc4() reads 255 bytes from chunk[48], then memcpy()\n   writes 255 bytes into msg[], both far out of bounds.\n\n2. chunk[48] overflow: curchunk_len can reach 63 (6-bit field). chunk[] is\n   only 48 bytes. Multi-iteration payload assembly appends 16-byte blocks\n   until curchunk_idx reaches curchunk_len, writing up to 15 bytes past\n   the end of chunk[] into msg[].\n\n3. msg[256] overflow: each chunk contributes (curchunk_len-1) bytes to\n   msg[]. No check ensures curlen + (curchunk_len-1) stays within msg[256],\n   so the memcpy can spill into adjacent struct fields.\n\nAll three are reachable from any DP MST device that can forge sideband\nreply messages on a physical connection.",
  "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": "6.1.183",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-68278"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ef2ecb6cf268debf3890df99fea01b6452dcf78e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d4e05dedb252ed3e540a0c9be511e427f098110a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4d5109075a787de28c9e89940f9dee45269f91fa"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/53937a2787d29c7a460e984dc4f20ff6ac91dc65"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ef0dbcc200c3389f1f781ab181932a97e54b51af"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1e5827839ad0ceb0079d1560c321fa3656b54f21"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a6366b551079c79bf7bdbadd74c97358bcfe2d58"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/55bd5e685bda455b9b50c835f8c8442d52a344a3"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-23T12:46:35Z"
  }
}