{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-52993",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-52993"
  ],
  "published": "2026-06-24T16:31:02Z",
  "summary": "tipc: fix double-free in tipc_buf_append()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix double-free in tipc_buf_append()\n\ntipc_msg_validate() can potentially reallocate the skb it is validating,\nfreeing the old one.  In tipc_buf_append(), it was being called with a\npointer to a local variable which was a copy of the caller's skb\npointer.\n\nIf the skb was reallocated and validation subsequently failed, the error\nhandling path would free the original skb pointer, which had already\nbeen freed, leading to double-free.\n\nFix this by checking if head now points to a newly allocated reassembled\nskb.  If it does, reassign *headbuf for later freeing operations.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "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-2026-52993"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 9.8,
      "cvss_v3_severity": "Critical",
      "scenario": "AV:N - TIPC fragment reassembly is reachable from off-node packets via configured TIPC bearers, including the UDP media path over IP. The most severe reasonable deployment is a TIPC UDP cluster service reachable over a network.\nAC:L - A malicious TIPC peer can craft the fragment sequence to inflate the reassembled skb truesize and make the copied inner message fail validation. No attacker-uncontrolled race or rare condition is required.\nPR:N - No target credentials or local account are required to send TIPC packets to an exposed bearer and establish/use the link path. The checks are TIPC discovery/link state checks, not user authentication.\nUI:N - Exploitation is packet-driven and does not require a victim user to open a file, mount anything, or take any other action.\nS:U - The bug corrupts kernel networking memory within the same kernel security authority. It does not cross a separate scope such as guest-to-host or an IOMMU boundary.\nC:H - The double-free of an skb is kernel heap memory corruption and can be leveraged as a use-after-free primitive. Conservatively, this supports high confidentiality impact.\nI:H - The double-free/use-after-free condition can be shaped into kernel memory corruption and potential control-flow or data modification primitives. Conservatively, this supports high integrity impact.\nA:H - Even without full exploitation, double-free of a kernel skb can trigger kernel heap corruption, oops, panic, or networking stack crash. This is high availability impact."
    }
  }
}