---
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:

  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 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'
---

## Overview

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

## 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`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.