FKIE_CVE-2026-74363
Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:19
Severity
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 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
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/inode.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ea1c243c39e32b7fc1c2edfe32081ff7e30a877c",
"status": "affected",
"version": "e28616ca3d67e745ecb2f10eba4a626e1fc9a203",
"versionType": "git"
},
{
"lessThan": "5fecb71c10c28aef276ba49c718dc961745fdcf0",
"status": "affected",
"version": "743a620c661994c7f0938e6dd32fb0883fb1e0ea",
"versionType": "git"
},
{
"lessThan": "c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2",
"status": "affected",
"version": "b6e9645be9eb93f7aff3ca887f8edb6f1d63358f",
"versionType": "git"
},
{
"lessThan": "53649846e0437d1d9b7cb993cfe54c367addf7ae",
"status": "affected",
"version": "ee04cff9ed4d6bb25802f5cecfcd0750500410f3",
"versionType": "git"
},
{
"lessThan": "61f19729728243c82476dee31315143ed3275e7f",
"status": "affected",
"version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
"versionType": "git"
},
{
"lessThan": "0497ff765746d9b2d17445c8f7cc737b36c0152a",
"status": "affected",
"version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
"versionType": "git"
},
{
"lessThan": "b93c55b4932dd7e32dca8cf34a3443cc87a02906",
"status": "affected",
"version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
"versionType": "git"
},
{
"status": "affected",
"version": "de2d2baecc84cc7fca52eec2b9b55d89c93e3565",
"versionType": "git"
},
{
"lessThan": "5.15.212",
"status": "affected",
"version": "5.15.195",
"versionType": "semver"
},
{
"lessThan": "6.1.178",
"status": "affected",
"version": "6.1.157",
"versionType": "semver"
},
{
"lessThan": "6.6.145",
"status": "affected",
"version": "6.6.113",
"versionType": "semver"
},
{
"lessThan": "6.12.97",
"status": "affected",
"version": "6.12.54",
"versionType": "semver"
},
{
"lessThan": "6.18",
"status": "affected",
"version": "6.17.4",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/bpf/inode.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"lessThan": "6.18",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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 inode cleanup from -\u003efree_inode()\ninto -\u003edestroy_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-\u003ei_opflags (offset +2) inside current_time() -\u003e 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 -\u003edestroy_inode() called immediately, can sleep, use for blocking\n cleanup e.g. bpf_any_put()\n -\u003efree_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"
}
],
"id": "CVE-2026-74363",
"lastModified": "2026-08-17T06:19:31.050",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-15T06:22:37.900",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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