{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74556","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.916Z","datePublished":"2026-08-15T12:28:01.359Z","dateUpdated":"2026-08-19T16:38:57.393Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-19T16:38:57.393Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer\n\niscsi_tcp_hdr_dissect() receives the data segment of several PDU types\ninto the fixed-size conn->data buffer, which is allocated for\nISCSI_DEF_MAX_RECV_SEG_LEN (8192) bytes.  For the LOGIN_RSP, TEXT_RSP,\nREJECT and ASYNC_EVENT opcodes the dissect path already rejects a PDU\nwhose DataSegmentLength exceeds that buffer.\n\nThe SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) path also copies its\ndata segment (sense/response data) into conn->data via\niscsi_tcp_data_recv_prep(), but it does so without the same check.  The\nonly upstream bound on in.datalen is conn->max_recv_dlength, the\ninitiator's advertised MaxRecvDataSegmentLength, which is commonly\nnegotiated well above 8192 (open-iscsi defaults to 262144).  A target\nthat returns a SCSI Response with a DataSegmentLength between 8193 and\nmax_recv_dlength therefore overflows the 8192-byte conn->data buffer.\n\nOnce the same bound applies, ISCSI_OP_SCSI_CMD_RSP is handled exactly\nlike those responses: bound the data segment, receive it into conn->data\nwhen present, and otherwise complete the PDU with no data.  Fold the\nopcode into that case group rather than duplicating the check."}],"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 - A malicious or compromised iSCSI target delivers crafted SCSI Command Response PDUs over the established TCP iSCSI session; reception flows through iscsi_sw_tcp_recv/iscsi_tcp_recv_skb into iscsi_tcp_hdr_dissect without local access.\nAC:L - The attacker controls the target and can set DataSegmentLength between 8193 and negotiated max_recv_dlength (open-iscsi commonly 262144) on SCSI_CMD_RSP for any outstanding command ITT; no races or victim-specific heap layout are required.\nPR:N - No privileges on the victim host are needed; a remote attacker acting as or MITMing the iSCSI target sends malicious responses after session login, independent of victim user accounts or capabilities.\nUI:N - On systems with persistent iSCSI sessions (cloud VMs, SAN-boot hosts, Kubernetes iSCSI volumes), exploitation triggers automatically during normal SCSI I/O when command responses are received; no victim action is needed at attack time.\nS:U - Heap corruption is confined to the kernel iSCSI initiator on the affected host; successful exploitation yields kernel compromise or DoS within the same security authority, not a VM escape or cross-boundary scope change.\nC:H - iscsi_tcp_segment_recv memcpy writes up to max_recv_dlength bytes into an 8192-byte conn->data buffer, causing a large heap overflow whose controlled corruption can be leveraged for arbitrary kernel memory disclosure.\nI:H - Attacker-controlled response data is copied past the fixed conn->data allocation via iscsi_tcp_data_recv_prep/iscsi_segment_init_linear, enabling heap metadata/object corruption exploitable for arbitrary kernel write and privilege escalation.\nA:H - Overflowing the conn->data heap buffer can immediately corrupt adjacent kernel allocations and cause oops/panic; a malicious target can repeatedly trigger this on active sessions to deny storage availability."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/libiscsi_tcp.c"],"versions":[{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"a51812842084fd390590ab8dc0431f10c73ddc56","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"a8f94cc9f0e5759252551be3a172960c57f21f54","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"f1a3a51fc5dba0e99532379665069f1700da6b44","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"c97b5265cc47775f77fd2a23d6bde0426997b233","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"084af0253673425ce2ae62e3c7f74f0dd023711b","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"72815741715bd41556dac5eeb068bf0f8af06ee7","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676","status":"affected","versionType":"git"},{"version":"a081c13e39b5c17052a7b46fafa61019c4c110ff","lessThan":"c1dea15f819cded9b3faf58f8bec72323568b6e6","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/scsi/libiscsi_tcp.c"],"versions":[{"version":"2.6.29","status":"affected"},{"version":"0","lessThan":"2.6.29","status":"unaffected","versionType":"semver"},{"version":"5.10.265","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.216","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.183","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.151","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.103","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.44","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.8","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a51812842084fd390590ab8dc0431f10c73ddc56"},{"url":"https://git.kernel.org/stable/c/a8f94cc9f0e5759252551be3a172960c57f21f54"},{"url":"https://git.kernel.org/stable/c/f1a3a51fc5dba0e99532379665069f1700da6b44"},{"url":"https://git.kernel.org/stable/c/c97b5265cc47775f77fd2a23d6bde0426997b233"},{"url":"https://git.kernel.org/stable/c/084af0253673425ce2ae62e3c7f74f0dd023711b"},{"url":"https://git.kernel.org/stable/c/72815741715bd41556dac5eeb068bf0f8af06ee7"},{"url":"https://git.kernel.org/stable/c/b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676"},{"url":"https://git.kernel.org/stable/c/c1dea15f819cded9b3faf58f8bec72323568b6e6"}],"title":"scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer","x_generator":{"engine":"bippy-1.2.0"}}}}