{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-90011", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-90011" ], "published": "2026-09-16T10:32:03Z", "summary": "scsi: target: iscsi: Reserve a terminator byte for the login payload", "details": "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.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.188", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-90011" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/5fac79f248c37774d1dd761406f83d25ca6ff8e4" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6ddddcad436d8e6e619204d3c848147ff2f5bf1e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b19dc17ed963ac36c0db4b52a1803fb11169f91f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/eb9dadf4d552ebe10644871c5189286552aa48f5" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/1624bff4c5118ad494d50ad94d44f22064667a7f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/3ddf3ea291a0ef2ea93b82e158960ac2cc42302b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f4825922d2fb371e2b969697d792077f1b62b62c" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-09-16T14:40:32Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 9.1, "cvss_v3_severity": "Critical", "scenario": "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." } } }