{"id":"CVE-2025-40341","summary":"futex: Don't leak robust_list pointer on exec race","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Don't leak robust_list pointer on exec race\n\nsys_get_robust_list() and compat_get_robust_list() use ptrace_may_access()\nto check if the calling task is allowed to access another task's\nrobust_list pointer. This check is racy against a concurrent exec() in the\ntarget process.\n\nDuring exec(), a task may transition from a non-privileged binary to a\nprivileged one (e.g., setuid binary) and its credentials/memory mappings\nmay change. If get_robust_list() performs ptrace_may_access() before\nthis transition, it may erroneously allow access to sensitive information\nafter the target becomes privileged.\n\nA racy access allows an attacker to exploit a window during which\nptrace_may_access() passes before a target process transitions to a\nprivileged state via exec().\n\nFor example, consider a non-privileged task T that is about to execute a\nsetuid-root binary. An attacker task A calls get_robust_list(T) while T\nis still unprivileged. Since ptrace_may_access() checks permissions\nbased on current credentials, it succeeds. However, if T begins exec\nimmediately afterwards, it becomes privileged and may change its memory\nmappings. Because get_robust_list() proceeds to access T-\u003erobust_list\nwithout synchronizing with exec() it may read user-space pointers from a\nnow-privileged process.\n\nThis violates the intended post-exec access restrictions and could\nexpose sensitive memory addresses or be used as a primitive in a larger\nexploit chain. Consequently, the race can lead to unauthorized\ndisclosure of information across privilege boundaries and poses a\npotential security risk.\n\nTake a read lock on signal-\u003eexec_update_lock prior to invoking\nptrace_may_access() and accessing the robust_list/compat_robust_list.\nThis ensures that the target task's exec state remains stable during the\ncheck, allowing for consistent and synchronized validation of\ncredentials.","modified":"2026-04-02T12:48:22.421844Z","published":"2025-12-09T04:09:58.392Z","related":["MGASA-2026-0017","MGASA-2026-0018"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40341.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3b4222494489f6d4b8705a496dab03384b7ca998"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4aced32596ead1820b7dbd8e40d30b30dc1f3ad4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6511984d1aa1360181bcafb1ca75df7f291ef237"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6b54082c3ed4dc9821cdf0edb17302355cc5bb45"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b524455a51feb6013df3a5dba3160487b2e8e22a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40341.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40341"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0771dfefc9e538f077d0b43b6dec19a5a67d0e70"},{"fixed":"6511984d1aa1360181bcafb1ca75df7f291ef237"},{"fixed":"4aced32596ead1820b7dbd8e40d30b30dc1f3ad4"},{"fixed":"3b4222494489f6d4b8705a496dab03384b7ca998"},{"fixed":"b524455a51feb6013df3a5dba3160487b2e8e22a"},{"fixed":"6b54082c3ed4dc9821cdf0edb17302355cc5bb45"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40341.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.17"},{"fixed":"6.1.159"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.117"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.58"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40341.json"}}],"schema_version":"1.7.5"}