Vulnerability-Lookup

FKIE_CVE-2026-64102

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:17

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Reject MPA FPDU length underflow before signed receive math A malicious connected siw peer can send an iWARP FPDU whose MPA length field (c_hdr->mpa_len, 16 bit big-endian, peer-controlled) is smaller than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode] .hdr_len, but never compares mpa_len against that header length. siw_tcp_rx_data() then derives srx->fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd + MPA_HDR_SIZE; where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below hdr_len - MPA_HDR_SIZE underflows to a negative int. The signed value then flows into siw_proc_write()/siw_proc_rresp() as bytes = min(srx->fpdu_part_rem, srx->skb_new); is handed to siw_check_mem() as an int len (whose interval check addr + len > mem->va + mem->len is satisfied for a valid base when len is negative), and reaches siw_rx_data() -> siw_rx_kva() / siw_rx_umem() -> skb_copy_bits() as a signed copy length. The header copy branch in skb_copy_bits() promotes that to size_t, producing a multi-gigabyte read. KASAN under a KUnit harness that drives the real kernel TCP receive path -- a loopback AF_INET socketpair, the malformed FPDU written via kernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock dispatching to siw_tcp_rx_data -- reports: BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480 Read of size 4294967295 at addr ffff888... Call Trace: skb_copy_bits siw_rx_kva siw_rx_data siw_check_mem siw_proc_write siw_tcp_rx_data __tcp_read_sock siw_qp_llp_data_ready tcp_data_ready tcp_data_queue Add the missing invariant at the earliest point where the peer header is fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly the value the siw transmitter uses as the minimum mpa_len for each opcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the protocol contract. Out-of-range FPDUs terminate the connection with TERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which is RFC 5044 Section 8 error code 3 ("Marker and ULPDU Length fields do not agree on the start of an FPDU"), the correct framing-error class for this inconsistency.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0ce1bc9e46ecabe84772bb561e373c0d9876d6f2
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/1012896f4225e8f801ff3c1648023845b66dfb11
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/14553be882d9ce91749c9d64041de66e34ad8e70
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/33a8b5e971e294ec2a7b74211c545e09efd8e9ac
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/4a331582011d9e8089af8aa2a61ec6b4443bb245
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/683f7cfbf514193d63c0efa079f3352bde84c2e0
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/775b4dc9618a99a1fa48b57554041a5dc17e1336
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/sw/siw/siw_qp_rx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "683f7cfbf514193d63c0efa079f3352bde84c2e0",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "4a331582011d9e8089af8aa2a61ec6b4443bb245",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "33a8b5e971e294ec2a7b74211c545e09efd8e9ac",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "14553be882d9ce91749c9d64041de66e34ad8e70",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "1012896f4225e8f801ff3c1648023845b66dfb11",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "775b4dc9618a99a1fa48b57554041a5dc17e1336",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "0ce1bc9e46ecabe84772bb561e373c0d9876d6f2",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/sw/siw/siw_qp_rx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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",
  "lastModified": "2026-07-20T15:17:09.180",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T16:17:51.383",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0ce1bc9e46ecabe84772bb561e373c0d9876d6f2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1012896f4225e8f801ff3c1648023845b66dfb11"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/14553be882d9ce91749c9d64041de66e34ad8e70"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/33a8b5e971e294ec2a7b74211c545e09efd8e9ac"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4a331582011d9e8089af8aa2a61ec6b4443bb245"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/683f7cfbf514193d63c0efa079f3352bde84c2e0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/775b4dc9618a99a1fa48b57554041a5dc17e1336"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-64102 (GCVE-0-2026-64102)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:40 – Updated: 2026-07-20 13:43

Title

RDMA/siw: Reject MPA FPDU length underflow before signed receive math

Summary

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

8 references

URL	Tags
https://git.kernel.org/stable/c/683f7cfbf514193d6…
https://git.kernel.org/stable/c/4a331582011d9e808…
https://git.kernel.org/stable/c/33a8b5e971e294ec2…
https://git.kernel.org/stable/c/14553be882d9ce917…
https://git.kernel.org/stable/c/c7c0c0f4379dedec1…
https://git.kernel.org/stable/c/1012896f4225e8f80…
https://git.kernel.org/stable/c/775b4dc9618a99a1f…
https://git.kernel.org/stable/c/0ce1bc9e46ecabe84…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 683f7cfbf514193d63c0efa079f3352bde84c2e0 (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 4a331582011d9e8089af8aa2a61ec6b4443bb245 (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 33a8b5e971e294ec2a7b74211c545e09efd8e9ac (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 14553be882d9ce91749c9d64041de66e34ad8e70 (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2 (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 1012896f4225e8f801ff3c1648023845b66dfb11 (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 775b4dc9618a99a1fa48b57554041a5dc17e1336 (git) Affected: 8b6a361b8c482f22ac99c3273285ff16b23fba91 , < 0ce1bc9e46ecabe84772bb561e373c0d9876d6f2 (git)
Linux	Linux	Affected: 5.3 Unaffected: 0 , < 5.3 (semver) Unaffected: 5.10.258 , ≤ 5.10.* (semver) Unaffected: 5.15.209 , ≤ 5.15.* (semver) Unaffected: 6.1.175 , ≤ 6.1.* (semver) Unaffected: 6.6.142 , ≤ 6.6.* (semver) Unaffected: 6.12.92 , ≤ 6.12.* (semver) Unaffected: 6.18.34 , ≤ 6.18.* (semver) Unaffected: 7.0.11 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/sw/siw/siw_qp_rx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "683f7cfbf514193d63c0efa079f3352bde84c2e0",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "4a331582011d9e8089af8aa2a61ec6b4443bb245",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "33a8b5e971e294ec2a7b74211c545e09efd8e9ac",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "14553be882d9ce91749c9d64041de66e34ad8e70",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "1012896f4225e8f801ff3c1648023845b66dfb11",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "775b4dc9618a99a1fa48b57554041a5dc17e1336",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            },
            {
              "lessThan": "0ce1bc9e46ecabe84772bb561e373c0d9876d6f2",
              "status": "affected",
              "version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/sw/siw/siw_qp_rx.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.258",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.209",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.142",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.92",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T13:43:20.335Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/683f7cfbf514193d63c0efa079f3352bde84c2e0"
        },
        {
          "url": "https://git.kernel.org/stable/c/4a331582011d9e8089af8aa2a61ec6b4443bb245"
        },
        {
          "url": "https://git.kernel.org/stable/c/33a8b5e971e294ec2a7b74211c545e09efd8e9ac"
        },
        {
          "url": "https://git.kernel.org/stable/c/14553be882d9ce91749c9d64041de66e34ad8e70"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2"
        },
        {
          "url": "https://git.kernel.org/stable/c/1012896f4225e8f801ff3c1648023845b66dfb11"
        },
        {
          "url": "https://git.kernel.org/stable/c/775b4dc9618a99a1fa48b57554041a5dc17e1336"
        },
        {
          "url": "https://git.kernel.org/stable/c/0ce1bc9e46ecabe84772bb561e373c0d9876d6f2"
        }
      ],
      "title": "RDMA/siw: Reject MPA FPDU length underflow before signed receive math",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64102",
    "datePublished": "2026-07-19T15:40:06.776Z",
    "dateReserved": "2026-07-19T07:54:57.033Z",
    "dateUpdated": "2026-07-20T13:43:20.335Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

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FKIE_CVE-2026-64102

CVE-2026-64102 (GCVE-0-2026-64102)

Tags

Sightings

Nomenclature