{"cve":"CVE-2026-93191","nvd":{"published":"2026-09-17T17:18:15.307","modified":"2026-10-19T10:17:09.720","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmack: fix incorrect task context in smack_msg_queue_msgrcv\n\nThe smack_msg_queue_msgrcv() function incorrectly checks\nthe permissions of the 'current' task instead of the\n'target' task.\n\nIn the msgsnd() syscall path, if a receiver is already waiting,\nthe pipelined_send() optimization is used to push the message\ndirectly to the receiver task:\n\n    ipc/msg.c`pipelined_send():\n    ` smp_store_release(&msr->r_msg, msg)\n\nIn this case, the 'sender' (current) task performs the check\non behalf of the 'receiver' task (msr->r_tsk, passed as the\n'target' parameter):\n\n  ipc/msg.c`pipelined_send():\n  ` security_msg_queue_msgrcv(,, target := msr->r_tsk,,)\n\nHowever, smack_msg_queue_msgrcv() ignores the 'target' and\nchecks 'current':\n\n  smack_msg_queue_msgrcv(…)\n  ` smk_curacc_msq(isp, MAY_READWRITE); // current task\n\n'current' MAY satisfy smack_msg_queue_msgrcv r/w requirement,\nbut 'target' (the receiver task) might NOT;\nas a result, an unauthorized receiver gets the message,\nviolating MAC policy.\n\nTest:\n1) create a sysv message queue with label “foo”\n2) echo \"bar foo r\" >/smack/load2\n3) msgrcv(,,,0,MSG_NOERROR) in \"bar\"-labeled task.\n    The task is waiting for the messages ...\n4) msgsnd() from a \"foo\"-labeled task:\n\"bar\"-labeled task gets the message.\n\nThis patch fixes the issue by checking permission on the\n'target' task instead of 'current'.\n\n(2008-02-04, Casey Schaufler)","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/4e49f997ef0c569e09b42aab6bd38c7c54ea095d","https://git.kernel.org/stable/c/7be4bd21c50afa83c93799b0f16cf5bfa493194e","https://git.kernel.org/stable/c/c2ab27c2e11591524b1378c24ad18882a425d1fa","https://git.kernel.org/stable/c/d02c55e3ea82e41ea2c2026e08201e5daa4d0cfe","https://git.kernel.org/stable/c/dbece6c2f80b0470d8d99d7a016827dce99ed6e3"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-93191","score":0.00196,"percentile":0.09233,"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."]}