{"id":"CVE-2026-98479","state":"PUBLISHED","title":"scsi: libiscsi_tcp: Check the data direction of a Data-In PDU","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: libiscsi_tcp: Check the data direction of a Data-In PDU\n\nThe Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task\nand copies the PDU's data segment into that command's scatterlist without\nasking whether the command was reading. iscsi_tcp_r2t_rsp() in the same\nfile does ask, and rejects an R2T for a command that is not DMA_TO_DEVICE.\n\nA target that answers a WRITE command's ITT with a Data-In therefore has\nthe initiator write target-supplied bytes into the pages that write was\nabout to send. Those are the caller's own pinned pages for an O_DIRECT\nwrite, and page cache pages for a buffered one.\n\nObserved against a test target that emits one 512-byte Data-In naming a 128\nKB write's ITT, after the R2T for that write. With O_DIRECT the caller's\nbuffer ends up holding 512 bytes of the target's data while pwrite()\nreturns 131072. Buffered is quieter: pwrite() and fsync() both succeed,\nnothing is logged, and reading those blocks back returns the target's bytes\nout of the page cache without a command going on the wire.\n\nCheck the direction before using the scatterlist, the way the R2T path\nalready does.","publishedAt":"2026-10-18T15:15:53.663Z","updatedAt":"2026-10-24T14:09:01.805Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"79991b770fc3685b1d5cf805b659a879edd19931","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"8db1232945bc663fb94f300090a1fc108de99296","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"94e5bdd08e51c450d954bc592f591c233ca5c9df","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"de96dc11aee0d058927bff94a168e3c5c46483e2","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"e3b25bf2cf2496e85bc05b33360faf9fdf880e03","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"ee56b5e18f566c0b5a183379dcd63d402cebf2f8","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"24ffc919467d20951f0f132d1c75294e2e91e09b","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"bce07e2f37b5e4a427d36fd6b1c14067b27591db","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/libiscsi_tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","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":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/scsi/libiscsi_tcp.c"]}],"references":["https://git.kernel.org/stable/c/79991b770fc3685b1d5cf805b659a879edd19931","https://git.kernel.org/stable/c/8db1232945bc663fb94f300090a1fc108de99296","https://git.kernel.org/stable/c/94e5bdd08e51c450d954bc592f591c233ca5c9df","https://git.kernel.org/stable/c/de96dc11aee0d058927bff94a168e3c5c46483e2","https://git.kernel.org/stable/c/e3b25bf2cf2496e85bc05b33360faf9fdf880e03","https://git.kernel.org/stable/c/ee56b5e18f566c0b5a183379dcd63d402cebf2f8","https://git.kernel.org/stable/c/24ffc919467d20951f0f132d1c75294e2e91e09b","https://git.kernel.org/stable/c/bce07e2f37b5e4a427d36fd6b1c14067b27591db"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98479.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98479","state":"PUBLISHED","datePublished":"2026-10-18T15:15:53.663Z","dateUpdated":"2026-10-24T14:09:01.805Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.351Z"},"containers":{"cna":{"title":"scsi: libiscsi_tcp: Check the data direction of a Data-In PDU","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: libiscsi_tcp: Check the data direction of a Data-In PDU\n\nThe Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task\nand copies the PDU's data segment into that command's scatterlist without\nasking whether the command was reading. iscsi_tcp_r2t_rsp() in the same\nfile does ask, and rejects an R2T for a command that is not DMA_TO_DEVICE.\n\nA target that answers a WRITE command's ITT with a Data-In therefore has\nthe initiator write target-supplied bytes into the pages that write was\nabout to send. Those are the caller's own pinned pages for an O_DIRECT\nwrite, and page cache pages for a buffered one.\n\nObserved against a test target that emits one 512-byte Data-In naming a 128\nKB write's ITT, after the R2T for that write. With O_DIRECT the caller's\nbuffer ends up holding 512 bytes of the target's data while pwrite()\nreturns 131072. Buffered is quieter: pwrite() and fsync() both succeed,\nnothing is logged, and reading those blocks back returns the target's bytes\nout of the page cache without a command going on the wire.\n\nCheck the direction before using the scatterlist, the way the R2T path\nalready does."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"79991b770fc3685b1d5cf805b659a879edd19931","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"8db1232945bc663fb94f300090a1fc108de99296","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"94e5bdd08e51c450d954bc592f591c233ca5c9df","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"de96dc11aee0d058927bff94a168e3c5c46483e2","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"e3b25bf2cf2496e85bc05b33360faf9fdf880e03","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"ee56b5e18f566c0b5a183379dcd63d402cebf2f8","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"24ffc919467d20951f0f132d1c75294e2e91e09b","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","status":"affected","lessThan":"bce07e2f37b5e4a427d36fd6b1c14067b27591db","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/libiscsi_tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","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":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/scsi/libiscsi_tcp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/79991b770fc3685b1d5cf805b659a879edd19931"},{"url":"https://git.kernel.org/stable/c/8db1232945bc663fb94f300090a1fc108de99296"},{"url":"https://git.kernel.org/stable/c/94e5bdd08e51c450d954bc592f591c233ca5c9df"},{"url":"https://git.kernel.org/stable/c/de96dc11aee0d058927bff94a168e3c5c46483e2"},{"url":"https://git.kernel.org/stable/c/e3b25bf2cf2496e85bc05b33360faf9fdf880e03"},{"url":"https://git.kernel.org/stable/c/ee56b5e18f566c0b5a183379dcd63d402cebf2f8"},{"url":"https://git.kernel.org/stable/c/24ffc919467d20951f0f132d1c75294e2e91e09b"},{"url":"https://git.kernel.org/stable/c/bce07e2f37b5e4a427d36fd6b1c14067b27591db"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - A remote iSCSI target supplies the malicious SCSI Data-In PDU over routable TCP; iscsi_sw_tcp_data_ready() reaches iscsi_tcp_recv_skb(), iscsi_tcp_hdr_dissect(), and the patched iscsi_tcp_data_in().\nAC:L - iscsi_prep_scsi_cmd_pdu() exposes the live WRITE ITT to the target, which can deterministically return a Data-In with that ITT, the expected DataSN, and an in-range offset and length; no race or outside condition is required.\nPR:N - The receive path imposes no privilege or per-PDU authentication check on the connected target; iscsi_verify_itt() only validates the ITT's session age and index, and the target learns that ITT from the WRITE command.\nUI:N - After iscsi_queuecommand() submits an ordinary WRITE on a logged-in session, the target's Data-In is processed automatically by the TCP callback; exploitation requires no user approval or opening of attacker-supplied content.\nS:U - iscsi_tcp_hdr_dissect() redirects data into task->sc->sdb, affecting the initiator's caller pages or page cache under the same host-kernel security authority, without crossing a VM, IOMMU, or sandbox boundary.\nC:N - iscsi_tcp_segment_recv() only copies target-supplied bytes into the command scatterlist; this defect provides no path for reading initiator memory or returning unintended bytes to the target.\nI:H - iscsi_segment_seek_sg() makes the receive segment reference a WRITE command's sdb, after which iscsi_tcp_segment_recv() copies attacker-chosen bytes into an O_DIRECT caller buffer or buffered-write page-cache pages.\nA:N - iscsi_tcp_data_in() bounds the offset and DataSegmentLength to sdb.length, and iscsi_segment_seek_sg() rejects offsets outside the scatterlist; the demonstrated effect is silent bounded data corruption, not an oops, hang, or resource exhaustion."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-24T14:09:01.805Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}