bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs
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
CVE-2026-74363
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-74363
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "e28616ca3d67e745ecb2f10eba4a626e1fc9a203",
"lessThan": "ea1c243c39e32b7fc1c2edfe32081ff7e30a877c",
"versionType": "git"
},
{
"status": "affected",
"version": "743a620c661994c7f0938e6dd32fb0883fb1e0ea",
"lessThan": "5fecb71c10c28aef276ba49c718dc961745fdcf0",
"versionType": "git"
},
{
"status": "affected",
"version": "b6e9645be9eb93f7aff3ca887f8edb6f1d63358f",
"lessThan": "c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2",
"versionType": "git"
},
{
"status": "affected",
"version": "ee04cff9ed4d6bb25802f5cecfcd0750500410f3",
"lessThan": "53649846e0437d1d9b7cb993cfe54c367addf7ae",
"versionType": "git"
},
{
"status": "affected",
"version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
"lessThan": "61f19729728243c82476dee31315143ed3275e7f",
"versionType": "git"
},
{
"status": "affected",
"version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
"lessThan": "0497ff765746d9b2d17445c8f7cc737b36c0152a",
"versionType": "git"
},
{
"status": "affected",
"version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
"lessThan": "b93c55b4932dd7e32dca8cf34a3443cc87a02906",
"versionType": "git"
},
{
"status": "affected",
"version": "de2d2baecc84cc7fca52eec2b9b55d89c93e3565",
"versionType": "git"
},
{
"status": "affected",
"version": "5.15.195",
"lessThan": "5.15.212",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.157",
"lessThan": "6.1.178",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.113",
"lessThan": "6.6.145",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.12.54",
"lessThan": "6.12.97",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.17.4",
"lessThan": "6.18",
"versionType": "semver"
}
],
"programFiles": [
"kernel/bpf/inode.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/bpf/inode.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74363
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #33110 · Revision 1
- Added to Heist Feed
- Publisher date