{"api_version":"1","generated_at":"2026-07-20T14:42:17+00:00","cve":"CVE-2026-64102","urls":{"html":"https://cve.report/CVE-2026-64102","api":"https://cve.report/api/cve/CVE-2026-64102.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64102","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64102"},"summary":{"title":"RDMA/siw: Reject MPA FPDU length underflow before signed receive math","description":"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->mpa_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->fpdu_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->fpdu_part_rem, srx->skb_new);\n\nis handed to siw_check_mem() as an int len (whose interval check\naddr + len > mem->va + mem->len is satisfied for a valid base when\nlen is negative), and reaches siw_rx_data() -> siw_rx_kva() /\nsiw_rx_umem() -> 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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:51","updated_at":"2026-07-19 16:17:51"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/683f7cfbf514193d63c0efa079f3352bde84c2e0","name":"https://git.kernel.org/stable/c/683f7cfbf514193d63c0efa079f3352bde84c2e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/775b4dc9618a99a1fa48b57554041a5dc17e1336","name":"https://git.kernel.org/stable/c/775b4dc9618a99a1fa48b57554041a5dc17e1336","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2","name":"https://git.kernel.org/stable/c/c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/14553be882d9ce91749c9d64041de66e34ad8e70","name":"https://git.kernel.org/stable/c/14553be882d9ce91749c9d64041de66e34ad8e70","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1012896f4225e8f801ff3c1648023845b66dfb11","name":"https://git.kernel.org/stable/c/1012896f4225e8f801ff3c1648023845b66dfb11","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/33a8b5e971e294ec2a7b74211c545e09efd8e9ac","name":"https://git.kernel.org/stable/c/33a8b5e971e294ec2a7b74211c545e09efd8e9ac","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4a331582011d9e8089af8aa2a61ec6b4443bb245","name":"https://git.kernel.org/stable/c/4a331582011d9e8089af8aa2a61ec6b4443bb245","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0ce1bc9e46ecabe84772bb561e373c0d9876d6f2","name":"https://git.kernel.org/stable/c/0ce1bc9e46ecabe84772bb561e373c0d9876d6f2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64102","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64102","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 683f7cfbf514193d63c0efa079f3352bde84c2e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 4a331582011d9e8089af8aa2a61ec6b4443bb245 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 33a8b5e971e294ec2a7b74211c545e09efd8e9ac git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 14553be882d9ce91749c9d64041de66e34ad8e70 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 1012896f4225e8f801ff3c1648023845b66dfb11 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 775b4dc9618a99a1fa48b57554041a5dc17e1336 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8b6a361b8c482f22ac99c3273285ff16b23fba91 0ce1bc9e46ecabe84772bb561e373c0d9876d6f2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.3","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.3 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.258 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.209 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.175 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.142 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.92 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.34 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.11 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"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->mpa_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->fpdu_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->fpdu_part_rem, srx->skb_new);\n\nis handed to siw_check_mem() as an int len (whose interval check\naddr + len > mem->va + mem->len is satisfied for a valid base when\nlen is negative), and reaches siw_rx_data() -> siw_rx_kva() /\nsiw_rx_umem() -> 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."}],"providerMetadata":{"dateUpdated":"2026-07-19T15:40:06.776Z","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":"2026-07-19T15:40:06.776Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:51","lastModifiedDate":"2026-07-19 16:17:51","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64102","Ordinal":"1","Title":"RDMA/siw: Reject MPA FPDU length underflow before signed receive","CVE":"CVE-2026-64102","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64102","Ordinal":"1","NoteData":"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->mpa_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->fpdu_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->fpdu_part_rem, srx->skb_new);\n\nis handed to siw_check_mem() as an int len (whose interval check\naddr + len > mem->va + mem->len is satisfied for a valid base when\nlen is negative), and reaches siw_rx_data() -> siw_rx_kva() /\nsiw_rx_umem() -> 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.","Type":"Description","Title":"RDMA/siw: Reject MPA FPDU length underflow before signed receive"}]}}}