{"cve":"CVE-2026-74556","nvd":{"published":"2026-08-15T13:18:01.047","modified":"2026-10-16T20:17:37.307","status":"Received","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":[],"references":["https://git.kernel.org/stable/c/084af0253673425ce2ae62e3c7f74f0dd023711b","https://git.kernel.org/stable/c/72815741715bd41556dac5eeb068bf0f8af06ee7","https://git.kernel.org/stable/c/a51812842084fd390590ab8dc0431f10c73ddc56","https://git.kernel.org/stable/c/a8f94cc9f0e5759252551be3a172960c57f21f54","https://git.kernel.org/stable/c/b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:10.689564601+00:00"},"epss":{"cve":"CVE-2026-74556","score":0.00399,"percentile":0.33853,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}