{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90011", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.781Z", "datePublished": "2026-09-16T10:33:18.793Z", "dateUpdated": "2026-10-19T08:56:25.054Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:56:25.054Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Reserve a terminator byte for the login payload\n\niscsi_target_check_login_request() rejects a login PDU whose\nDataSegmentLength exceeds MAX_KEY_VALUE_PAIRS, but the test is '>' and\nlogin->req_buf is allocated with exactly MAX_KEY_VALUE_PAIRS\nbytes. Since iscsit_get_login_rx() receives payload_length + padding\nbytes, where\n\n\tpadding = ((-payload_length) & 3);\n\nany payload_length from 8189 to 8192 fills the whole 8192 byte\nbuffer. The write stays in bounds, but no byte is left for a NUL\nterminator.\n\nThe buffer is subsequently consumed as a C string. In the CHAP path\nchap_check_algorithm() calls kstrdup(a_str), and extract_param() calls\nstrstr(in_buf, pattern) followed by strlen_semi(), none of which take a\nlength. convert_null_to_semi() additionally rewrites every embedded NUL\nto ';', so even a payload made of well formed NUL separated key=value\nrecords is left without a terminator. These walk past the end of the\nobject into adjacent slab memory. It is reachable by an unauthenticated\ninitiator against a portal configured for CHAP; when authentication is\nnot required iscsi_login_zero_tsih_s2() rewrites AuthMethod to None and\nthe CHAP path is never entered.\n\nAllocate one extra byte. kzalloc() zeroes it and nothing ever writes to\nit, as every writer copies to offset 0 for at most MAX_KEY_VALUE_PAIRS\nbytes, so the buffer is always terminated." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The LIO in-kernel iSCSI target accepts remote TCP connections on the iSCSI portal (typically port 3260); a crafted Login PDU is received by iscsit_accept_np()/iscsit_get_login_rx() and reaches the CHAP parsers over the network, the same exposure model as nfsd or ksmbd.\nAC:L - The attacker fully controls DataSegmentLength and the login payload. A CHAP_A PDU of 8189-8192 bytes with no NUL, or a second CHAP round where convert_null_to_semi() strips every terminator, makes kstrdup()/strstr() over-read adjacent slab deterministically; no race or victim-side layout is required.\nPR:N - The over-read runs in the CHAP login handshake before the password hash is checked, so no Linux account or capability is needed. Default TPG authentication is CHAP (TA_AUTHENTICATION=1), and chap_server_open() proceeds once target-side CHAP credentials exist, which is the normal CHAP deployment.\nUI:N - The attacker opens a TCP connection to the listening portal and sends the malicious Login PDUs; no victim user action such as mounting a volume or accepting a prompt is required.\nS:U - The unbounded C-string over-read and any resulting kernel oops stay inside the host iSCSI target's kernel security authority and do not by themselves cross a VM, IOMMU, or sandbox boundary.\nC:H - chap_check_algorithm() kstrdup()s the unterminated 8192-byte req_buf, and extract_param() uses unbounded strstr()/strlen_semi() after convert_null_to_semi() removes embedded NULs, producing an unbounded out-of-bounds read of adjacent kmalloc-8k slab that can disclose neighboring kernel objects.\nI:N - iscsit_get_login_rx() copies at most MAX_KEY_VALUE_PAIRS bytes into req_buf, so the network write stays in bounds; convert_null_to_semi() also writes only within payload_length. There is no out-of-bounds write or control-flow hijack primitive.\nA:H - strlen()/kstrdup()/strstr() walking past the kmalloc-8k login object into unmapped or guard pages causes a kernel oops, and the attacker can repeat the unauthenticated login against an exposed portal, denying service to the host and its iSCSI clients." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/target/iscsi/iscsi_target_login.c" ], "versions": [ { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "5fac79f248c37774d1dd761406f83d25ca6ff8e4", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "6ddddcad436d8e6e619204d3c848147ff2f5bf1e", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "b19dc17ed963ac36c0db4b52a1803fb11169f91f", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "eb9dadf4d552ebe10644871c5189286552aa48f5", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "1624bff4c5118ad494d50ad94d44f22064667a7f", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "3ddf3ea291a0ef2ea93b82e158960ac2cc42302b", "status": "affected", "versionType": "git" }, { "version": "e48354ce078c079996f89d715dfa44814b4eba01", "lessThan": "f4825922d2fb371e2b969697d792077f1b62b62c", "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/target/iscsi/iscsi_target_login.c" ], "versions": [ { "version": "3.1", "status": "affected" }, { "version": "0", "lessThan": "3.1", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "3.1", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.1", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5fac79f248c37774d1dd761406f83d25ca6ff8e4" }, { "url": "https://git.kernel.org/stable/c/6ddddcad436d8e6e619204d3c848147ff2f5bf1e" }, { "url": "https://git.kernel.org/stable/c/b19dc17ed963ac36c0db4b52a1803fb11169f91f" }, { "url": "https://git.kernel.org/stable/c/6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076" }, { "url": "https://git.kernel.org/stable/c/eb9dadf4d552ebe10644871c5189286552aa48f5" }, { "url": "https://git.kernel.org/stable/c/1624bff4c5118ad494d50ad94d44f22064667a7f" }, { "url": "https://git.kernel.org/stable/c/3ddf3ea291a0ef2ea93b82e158960ac2cc42302b" }, { "url": "https://git.kernel.org/stable/c/f4825922d2fb371e2b969697d792077f1b62b62c" } ], "title": "scsi: target: iscsi: Reserve a terminator byte for the login payload", "x_generator": { "engine": "bippy-1.2.0" } } } }