{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-68425",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-68425"
  ],
  "published": "2026-08-10T12:08:00Z",
  "summary": "IB/mad: Drop unmatched RMPP responses before reassembly",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nIB/mad: Drop unmatched RMPP responses before reassembly\n\nKernel-handled RMPP receive processing starts reassembly for active\nDATA responses before the response is matched to an outstanding send.\nThe normal match happens later, after ib_process_rmpp_recv_wc() has\neither assembled a complete message or consumed the segment.\n\nThat ordering lets an unsolicited response that routes to a kernel\nRMPP agent by the high TID bits allocate or extend RMPP receive state\nbefore the full TID and source address are checked against a real\nrequest. A reordered burst can therefore reach the receive-side\ninsertion path even though the response would not match any send.\n\nFor kernel-handled RMPP DATA responses, require the existing\nib_find_send_mad() match before entering RMPP reassembly. The matcher\nalready checks the full TID, management class and source address/GID\nagainst the agent wait, backlog and in-flight send lists. If there is\nno match, drop the response without creating RMPP state.\n\nThis leaves the RMPP window behavior unchanged and only rejects\nresponses that have no corresponding request.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/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": "6.1.183",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-68425"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/45416c87ebcece1e90f3bc5bc172d106b77c6b69"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9634fb1f4d404f36a20ffbcb8797369db69b06bb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bfb9e8243fd2099d1080d09222964d988f991d9b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/dfa535c94406c03d3f0c869ef3ba5528e395737c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6e1bd7f590b0ccfee07f7fe1d48b92059bd37d72"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/98d2d468b4faa1fdc68c0c6c238389906ee3490c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ad9c9ad3204f63a46f0f7de29687a8e512f05e29"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d2e52d610b9b09694261632340b801a421e0b0c5"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-19T16:47:12Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.1,
      "cvss_v3_severity": "High",
      "scenario": "AV:A - The attacker must be a node on the same InfiniBand fabric, sending unsolicited GSI (QP1) management datagrams to the victim port; MAD/SA traffic is subnet-local, matching the CVSS \"shared physical or logical network\" definition rather than routable network reach.\nAC:L - No race or unusual precondition is needed: the attacker just sends active RMPP DATA response MADs whose high TID bits name a kernel RMPP agent, and hi_tid is a small cyclic xarray index in [0,2^24) that is trivially enumerated or brute-forced.\nPR:N - The MAD receive path accepts unsolicited datagrams from any fabric peer with no authentication; the only gate is ib_mad_enforce_security() P_Key membership, which the default partition typically grants to every node on the subnet.\nUI:N - Reassembly state is created entirely from attacker-sent packets in the completion handler; no action by a local user or administrator is needed, and the always-registered ib_sa kernel agent is the target.\nS:U - The injected RMPP state, allocations and AH objects all live inside the kernel's own IB MAD layer on the same host, so the impact stays within a single security authority.\nC:N - The flaw creates unmatched reassembly state; it provides no out-of-bounds read, no kernel memory disclosure, and the ACKs the kernel emits echo only attacker-supplied header fields.\nI:L - An unauthenticated fabric peer can insert arbitrary unsolicited entries into the kernel agent's RMPP reassembly lists and make the kernel emit ACKs, and a colliding entry (SA TIDs come from a predictable tid++ counter) diverts and drops a legitimate SA response's segments \u2014 limited, bounded modification of kernel protocol state.\nA:H - Each unmatched segment allocates a mad_rmpp_recv, an AH and a retained ~1-2 KB MAD buffer held for 40 seconds with no matching request, so a burst causes unbounded memory/resource exhaustion, while the O(N) rmpp_list walks under an IRQ-disabled spinlock stall MAD processing and break SA/path resolution for the node."
    }
  }
}