{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "8b6a361b8c482f22ac99c3273285ff16b23fba91"
            },
            {
              "fixed": "683f7cfbf514193d63c0efa079f3352bde84c2e0"
            },
            {
              "fixed": "4a331582011d9e8089af8aa2a61ec6b4443bb245"
            },
            {
              "fixed": "33a8b5e971e294ec2a7b74211c545e09efd8e9ac"
            },
            {
              "fixed": "14553be882d9ce91749c9d64041de66e34ad8e70"
            },
            {
              "fixed": "c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2"
            },
            {
              "fixed": "1012896f4225e8f801ff3c1648023845b66dfb11"
            },
            {
              "fixed": "775b4dc9618a99a1fa48b57554041a5dc17e1336"
            },
            {
              "fixed": "0ce1bc9e46ecabe84772bb561e373c0d9876d6f2"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.3.0"
            },
            {
              "fixed": "5.10.258"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.209"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.175"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.142"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.92"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.34"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64102.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/siw: Reject MPA FPDU length underflow before signed receive math\n\nA malicious connected siw peer can send an iWARP FPDU whose MPA length\nfield (c_hdr-\u003empa_len, 16 bit big-endian, peer-controlled) is smaller\nthan the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP\nparses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode]\n.hdr_len, but never compares mpa_len against that header length.\n\nsiw_tcp_rx_data() then derives\n\n    srx-\u003efpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd\n                         + MPA_HDR_SIZE;\n\nwhere fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this\npoint. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest\non-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below\nhdr_len - MPA_HDR_SIZE underflows to a negative int.\n\nThe signed value then flows into siw_proc_write()/siw_proc_rresp() as\n\n    bytes = min(srx-\u003efpdu_part_rem, srx-\u003eskb_new);\n\nis handed to siw_check_mem() as an int len (whose interval check\naddr + len \u003e mem-\u003eva + mem-\u003elen is satisfied for a valid base when\nlen is negative), and reaches siw_rx_data() -\u003e siw_rx_kva() /\nsiw_rx_umem() -\u003e skb_copy_bits() as a signed copy length. The header\ncopy branch in skb_copy_bits() promotes that to size_t, producing a\nmulti-gigabyte read.\n\nKASAN under a KUnit harness that drives the real kernel TCP receive\npath -- a loopback AF_INET socketpair, the malformed FPDU written via\nkernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock\ndispatching to siw_tcp_rx_data -- reports:\n\n    BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480\n    Read of size 4294967295 at addr ffff888...\n    Call Trace:\n     skb_copy_bits\n     siw_rx_kva\n     siw_rx_data\n     siw_check_mem\n     siw_proc_write\n     siw_tcp_rx_data\n     __tcp_read_sock\n     siw_qp_llp_data_ready\n     tcp_data_ready\n     tcp_data_queue\n\nAdd the missing invariant at the earliest point where the peer header\nis fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly\nthe value the siw transmitter uses as the minimum mpa_len for each\nopcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the\nprotocol contract. Out-of-range FPDUs terminate the connection with\nTERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which\nis RFC 5044 Section 8 error code 3 (\"Marker and ULPDU Length fields\ndo not agree on the start of an FPDU\"), the correct framing-error\nclass for this inconsistency.",
  "id": "CVE-2026-64102",
  "modified": "2026-08-12T03:51:15.902447584Z",
  "published": "2026-07-19T15:40:06.776Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0ce1bc9e46ecabe84772bb561e373c0d9876d6f2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1012896f4225e8f801ff3c1648023845b66dfb11"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/14553be882d9ce91749c9d64041de66e34ad8e70"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/33a8b5e971e294ec2a7b74211c545e09efd8e9ac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4a331582011d9e8089af8aa2a61ec6b4443bb245"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/683f7cfbf514193d63c0efa079f3352bde84c2e0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/775b4dc9618a99a1fa48b57554041a5dc17e1336"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64102.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64102"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "RDMA/siw: Reject MPA FPDU length underflow before signed receive math"
}