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CVE-2026-74363

HIGHCVSS 7.8/10EPSS 0.17%

Last modified

CVE-2026-74363 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.17%

7.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= e28616ca3d67e745ecb2f10eba4a626e1fc9a203, < ea1c243c39e32b7fc1c2edfe32081ff7e30a877c; >= 743a620c661994c7f0938e6dd32fb0883fb1e0ea, < 5fecb71c10c28aef276ba49c718dc961745fdcf0; >= b6e9645be9eb93f7aff3ca887f8edb6f1d63358f, < c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2; >= ee04cff9ed4d6bb25802f5cecfcd0750500410f3, < 53649846e0437d1d9b7cb993cfe54c367addf7ae; >= 4f375ade6aa9f37fd72d7a78682f639772089eed, < 61f19729728243c82476dee31315143ed3275e7f; >= 4f375ade6aa9f37fd72d7a78682f639772089eed, < 0497ff765746d9b2d17445c8f7cc737b36c0152a; >= 4f375ade6aa9f37fd72d7a78682f639772089eed, < b93c55b4932dd7e32dca8cf34a3443cc87a02906; de2d2baecc84cc7fca52eec2b9b55d89c93e3565; >= 5.15.195, < 5.15.212; >= 6.1.157, < 6.1.178; >= 6.6.113, < 6.6.145; >= 6.12.54, < 6.12.97; >= 6.17.4, < 6.18
LinuxLinux6.18

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74363?
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
How severe is CVE-2026-74363?
CVE-2026-74363 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-74363?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST