{"id":"CVE-2026-74363","title":"bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs","summary":"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 ino…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= e28616ca3d67e745ecb2f10eba4a626e1fc9a203 < ea1c243c39e32b7fc1c2edfe32081ff7e30a877c","Linux >= 743a620c661994c7f0938e6dd32fb0883fb1e0ea < 5fecb71c10c28aef276ba49c718dc961745fdcf0","Linux >= b6e9645be9eb93f7aff3ca887f8edb6f1d63358f < c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2","Linux >= ee04cff9ed4d6bb25802f5cecfcd0750500410f3 < 53649846e0437d1d9b7cb993cfe54c367addf7ae","Linux >= 4f375ade6aa9f37fd72d7a78682f639772089eed < 61f19729728243c82476dee31315143ed3275e7f","Linux >= 4f375ade6aa9f37fd72d7a78682f639772089eed < 0497ff765746d9b2d17445c8f7cc737b36c0152a","Linux >= 4f375ade6aa9f37fd72d7a78682f639772089eed < b93c55b4932dd7e32dca8cf34a3443cc87a02906","Linux de2d2baecc84cc7fca52eec2b9b55d89c93e3565","Linux >= 5.15.195 < 5.15.212","Linux >= 6.1.157 < 6.1.178","Linux >= 6.6.113 < 6.6.145","Linux >= 6.12.54 < 6.12.97","Linux >= 6.17.4 < 6.18","Linux 6.18"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T18:54:33.862725Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:35.622Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74363","references":[{"url":"https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c"},{"url":"https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0"},{"url":"https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2"},{"url":"https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae"},{"url":"https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f"},{"url":"https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a"},{"url":"https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906"}],"tags":["cve.org"],"epss":0.00126,"epssPercentile":0.02031,"ingestedAt":"2026-10-16T19:46:24.375Z","slug":"CVE-2026-74363","body":"## Overview\n\nIn 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\n\n## Affected\n\n- `Linux >= e28616ca3d67e745ecb2f10eba4a626e1fc9a203 < ea1c243c39e32b7fc1c2edfe32081ff7e30a877c`\n- `Linux >= 743a620c661994c7f0938e6dd32fb0883fb1e0ea < 5fecb71c10c28aef276ba49c718dc961745fdcf0`\n- `Linux >= b6e9645be9eb93f7aff3ca887f8edb6f1d63358f < c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2`\n- `Linux >= ee04cff9ed4d6bb25802f5cecfcd0750500410f3 < 53649846e0437d1d9b7cb993cfe54c367addf7ae`\n- `Linux >= 4f375ade6aa9f37fd72d7a78682f639772089eed < 61f19729728243c82476dee31315143ed3275e7f`\n- `Linux >= 4f375ade6aa9f37fd72d7a78682f639772089eed < 0497ff765746d9b2d17445c8f7cc737b36c0152a`\n- `Linux >= 4f375ade6aa9f37fd72d7a78682f639772089eed < b93c55b4932dd7e32dca8cf34a3443cc87a02906`\n- `Linux de2d2baecc84cc7fca52eec2b9b55d89c93e3565`\n- `Linux >= 5.15.195 < 5.15.212`\n- `Linux >= 6.1.157 < 6.1.178`\n- `Linux >= 6.6.113 < 6.6.145`\n- `Linux >= 6.12.54 < 6.12.97`\n- `Linux >= 6.17.4 < 6.18`\n- `Linux 6.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}