{"id":"CVE-2026-98323","state":"PUBLISHED","title":"RDMA/siw: Bound fragmented header copies by the remaining length","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/siw: Bound fragmented header copies by the remaining length\n\nsiw_get_hdr() can receive an extended DDP/RDMAP header across more than\none TCP callback. The first callback may receive most of the header,\nwhile the next one still limits the copy to hdrlen - MIN_DDP_HDR instead\nof the number of missing bytes. This makes the destination move past the\nend of the header and overwrite the receive state, including\nfpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd\nvalue as a copy offset, which creates an OOB write.\n\nUse the number of header bytes already received when calculating the\nnext copy length.","publishedAt":"2026-10-06T08:46:17.150Z","updatedAt":"2026-10-19T09:17:33.779Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e3917c85f41ef1df64e27dc0e46ab0d803c5e73e","status":"affected","lessThan":"2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7","versionType":"git"},{"version":"308cd50f174c95a507527037f4de1a0396aa4325","status":"affected","lessThan":"af9f5b474a260ad23ffb9793d716a5e3bbce3b48","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"262dcd809723723ed8a4e05437ec7e9c21a8f17e","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"eb4d7a946970469b3ab0c762432bf161d5b0836c","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"8628f8ebf41669302513fb3f0bf0eba38b226742","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"b72dcfb9bf1f0f0147cda03dc59e4002a315067f","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"9ff797e516dbc1ecb73701ec4c24055712d44411","versionType":"git"},{"version":"e09caa38e10bcf027100cc22b0e3cc745a39ef0a","status":"affected","versionType":"git"},{"version":"0c14f795a9eab9344230f9933798b8ee496f497d","status":"affected","versionType":"git"},{"version":"7fada7c6962219b6fc4ff4e62e46a936af110dd9","status":"affected","versionType":"git"},{"version":"5.10.150","status":"affected","lessThan":"5.10.271","versionType":"semver"},{"version":"5.15.75","status":"affected","lessThan":"5.15.222","versionType":"semver"},{"version":"5.4.220","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.19.17","status":"affected","lessThan":"5.20","versionType":"semver"},{"version":"6.0.3","status":"affected","lessThan":"6.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/siw/siw_qp_rx.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.54","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.8","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/siw/siw_qp_rx.c"]}],"references":["https://git.kernel.org/stable/c/2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7","https://git.kernel.org/stable/c/af9f5b474a260ad23ffb9793d716a5e3bbce3b48","https://git.kernel.org/stable/c/262dcd809723723ed8a4e05437ec7e9c21a8f17e","https://git.kernel.org/stable/c/eb4d7a946970469b3ab0c762432bf161d5b0836c","https://git.kernel.org/stable/c/8628f8ebf41669302513fb3f0bf0eba38b226742","https://git.kernel.org/stable/c/b72dcfb9bf1f0f0147cda03dc59e4002a315067f","https://git.kernel.org/stable/c/e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d","https://git.kernel.org/stable/c/9ff797e516dbc1ecb73701ec4c24055712d44411"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98323.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98323","state":"PUBLISHED","datePublished":"2026-10-06T08:46:17.150Z","dateUpdated":"2026-10-19T09:17:33.779Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.340Z"},"containers":{"cna":{"title":"RDMA/siw: Bound fragmented header copies by the remaining length","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/siw: Bound fragmented header copies by the remaining length\n\nsiw_get_hdr() can receive an extended DDP/RDMAP header across more than\none TCP callback. The first callback may receive most of the header,\nwhile the next one still limits the copy to hdrlen - MIN_DDP_HDR instead\nof the number of missing bytes. This makes the destination move past the\nend of the header and overwrite the receive state, including\nfpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd\nvalue as a copy offset, which creates an OOB write.\n\nUse the number of header bytes already received when calculating the\nnext copy length."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e3917c85f41ef1df64e27dc0e46ab0d803c5e73e","status":"affected","lessThan":"2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7","versionType":"git"},{"version":"308cd50f174c95a507527037f4de1a0396aa4325","status":"affected","lessThan":"af9f5b474a260ad23ffb9793d716a5e3bbce3b48","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"262dcd809723723ed8a4e05437ec7e9c21a8f17e","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"eb4d7a946970469b3ab0c762432bf161d5b0836c","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"8628f8ebf41669302513fb3f0bf0eba38b226742","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"b72dcfb9bf1f0f0147cda03dc59e4002a315067f","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d","versionType":"git"},{"version":"754209850df8367c954ac1de7671c7430b1f342c","status":"affected","lessThan":"9ff797e516dbc1ecb73701ec4c24055712d44411","versionType":"git"},{"version":"e09caa38e10bcf027100cc22b0e3cc745a39ef0a","status":"affected","versionType":"git"},{"version":"0c14f795a9eab9344230f9933798b8ee496f497d","status":"affected","versionType":"git"},{"version":"7fada7c6962219b6fc4ff4e62e46a936af110dd9","status":"affected","versionType":"git"},{"version":"5.10.150","status":"affected","lessThan":"5.10.271","versionType":"semver"},{"version":"5.15.75","status":"affected","lessThan":"5.15.222","versionType":"semver"},{"version":"5.4.220","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.19.17","status":"affected","lessThan":"5.20","versionType":"semver"},{"version":"6.0.3","status":"affected","lessThan":"6.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/siw/siw_qp_rx.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.54","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.8","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/siw/siw_qp_rx.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7"},{"url":"https://git.kernel.org/stable/c/af9f5b474a260ad23ffb9793d716a5e3bbce3b48"},{"url":"https://git.kernel.org/stable/c/262dcd809723723ed8a4e05437ec7e9c21a8f17e"},{"url":"https://git.kernel.org/stable/c/eb4d7a946970469b3ab0c762432bf161d5b0836c"},{"url":"https://git.kernel.org/stable/c/8628f8ebf41669302513fb3f0bf0eba38b226742"},{"url":"https://git.kernel.org/stable/c/b72dcfb9bf1f0f0147cda03dc59e4002a315067f"},{"url":"https://git.kernel.org/stable/c/e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d"},{"url":"https://git.kernel.org/stable/c/9ff797e516dbc1ecb73701ec4c24055712d44411"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The malformed input is the remote iWARP peer's own MPA/DDP/RDMAP header bytes on the siw TCP connection. The peer splits an extended header (e.g. RDMA Read Request, 44 bytes) across TCP segments, and siw_qp_llp_data_ready() -> tcp_read_sock() -> siw_tcp_rx_data() -> siw_get_hdr() parses them. The transport is routable TCP.\nAC:L - The peer fully controls TCP segmentation, so it can deterministically end a segment with fpdu_part_rcvd between 16 and hdrlen. The next segment then copies hdrlen-16 bytes at that offset. No race or state outside the attacker's control is involved beyond siw serving an iWARP listener.\nPR:N - Once the MPA exchange puts the QP in RTS, siw_get_hdr() parses every incoming FPDU header, and neither MPA nor DDP authenticates the peer. ULP authorisation (such as an nvmet-rdma host NQN check) only arrives in messages parsed by this same path, so the overflow fires before any credential check.\nUI:N - No victim action is needed. The attacker connects to the iWARP service and sends crafted fragmented FPDUs, and siw processes them in its sk_data_ready callback.\nS:U - The corruption is confined to kernel memory of the host running siw (struct siw_qp and its neighbours). That is the same security authority as the vulnerable component, with no VM or IOMMU boundary crossed.\nC:H - The overflow writes peer bytes over siw_rx_stream fields after hdr, including fpdu_part_rcvd. A negative fpdu_part_rcvd then makes skb_copy_bits() write to c_hdr plus an attacker-chosen offset. A controlled kernel write like this can be turned into arbitrary kernel memory disclosure.\nI:H - siw_get_hdr() copies up to hdrlen-17 attacker bytes past srx->hdr (27 for rreq), overwriting the receive state. The next callback uses the corrupted negative fpdu_part_rcvd as the destination offset of skb_copy_bits(), giving an out-of-bounds kernel write whose offset and data are attacker-controlled.\nA:H - Corrupting fpdu_part_rcvd/fpdu_part_rem and writing out of bounds from siw_qp crashes or panics the kernel. A remote peer can repeat this on every connection."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:17:33.779Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.150","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.75","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.18.54"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.2.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.220"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19.17"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}