{"id":"CVE-2026-74363","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74363","summary":"bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: fix UAF by restoring RCU-delayed inode freeing in bpffs\n\ncommit 4f375ade6aa9 (\"bpf: Avoid RCU context warning when unpinning\nhtab with internal structs\") moved inode cleanup from ->free_inode()\ninto ->destroy_inode() to avoid sleeping in RCU context when calling\nbpf_any_put(). However this removed the RCU delay on freeing the\ninode itself and the cached symlink body (i_link), both of which\ncan be accessed by RCU pathwalk (pick_link, may_lookup etc.).\n\nThis causes a use-after-free when a concurrent unlinkat() drops the\nlast inode reference and destroy_inode() frees the inode immediately,\nwhile another task is still walking the path in RCU mode and reads\ninode->i_opflags (offset +2) inside current_time() -> is_mgtime().\n\nKASAN reports:\n  BUG: KASAN: slab-use-after-free in is_mgtime include/linux/fs.h:2313\n  Read of size 2 at addr ffff8880407e4282 (offset +2 = i_opflags)\n\nThe rules (per Al Viro):\n  ->destroy_inode()  called immediately, can sleep, use for blocking\n                     cleanup e.g. bpf_any_put()\n  ->free_inode()     called after RCU grace period, use for freeing\n                     inode and anything RCU-accessible e.g. i_link\n\nFix: split the two concerns properly:\n  - keep bpf_any_put() in bpf_destroy_inode() since it is blocking\n    and needs to run promptly\n  - introduce bpf_free_inode() to handle kfree(i_link) and\n    free_inode_nonrcu() with proper RCU delay, preventing the UAF","published":"2026-08-15T05:58:46.220Z","modified":"2026-08-18T03:56:47.128068161Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.15.212"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74363.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74363"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:47.128068161Z"}}