CVE-2026-74363bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs
Updated under an hour ago ()
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In the Linux kernel, the following vulnerability has been resolved: bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs commit 4f375ade6aa9 ("bpf: Avoid RCU context warning when unpinning htab with internal structs") moved inode cleanup from ->free_inode() into ->destroy_inode() to avoid sleeping in RCU context when calling bpf_any_put(). However this removed the RCU delay on freeing the inode itself and the cached symlink body (i_link), both of which can be accessed by RCU pathwalk (pick_link, may_lookup etc.). This causes a use-after-free when a concurrent unlinkat() drops the last inode reference and destroy_inode() frees the inode immediately, while another task is still walking the path in RCU mode and reads inode->i_opflags (offset +2) inside current_time() -> is_mgtime(). KASAN reports: BUG: KASAN: slab-use-after-free in is_mgtime include/linux/fs.h:2313 Read of size 2 at addr ffff8880407e4282 (offset +2 = i_opflags) The rules (per Al Viro): ->destroy_inode() called immediately, can sleep, use for blocking cleanup e.g. bpf_any_put() ->free_inode() called after RCU grace period, use for freeing inode and anything RCU-accessible e.g. i_link Fix: split the two concerns properly: - keep bpf_any_put() in bpf_destroy_inode() since it is blocking and needs to run promptly - introduce bpf_free_inode() to handle kfree(i_link) and free_inode_nonrcu() with proper RCU delay, preventing the UAF
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from e28616ca3d67e745ecb2f10eba4a626e1fc9a203 before ea1c243c39e32b7fc1c2edfe32081ff7e30a877c; 743a620c661994c7f0938e6dd32fb0883fb1e0ea builds before 5fecb71c10c28aef276ba49c718dc961745fdcf0; from b6e9645be9eb93f7aff3ca887f8edb6f1d63358f before c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2; from ee04cff9ed4d6bb25802f5cecfcd0750500410f3 before 53649846e0437d1d9b7cb993cfe54c367addf7ae; from 4f375ade6aa9f37fd72d7a78682f639772089eed before 61f19729728243c82476dee31315143ed3275e7f; from 4f375ade6aa9f37fd72d7a78682f639772089eed before 0497ff765746d9b2d17445c8f7cc737b36c0152a; from 4f375ade6aa9f37fd72d7a78682f639772089eed before b93c55b4932dd7e32dca8cf34a3443cc87a02906; de2d2baecc84cc7fca52eec2b9b55d89c93e3565; and 5 more ranges | CNA record |
References
- https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c
- https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0
- https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2
- https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae
- https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f
- https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a
- https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.