FKIE_CVE-2026-46052
Vulnerability from fkie_nvd - Published: 2026-05-27 14:17 - Updated: 2026-06-19 13:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ceph: only d_add() negative dentries when they are unhashed
Ceph can call d_add(dentry, NULL) on a negative dentry that is already
present in the primary dcache hash.
In the current VFS that is not safe. d_add() goes through __d_add()
to __d_rehash(), which unconditionally reinserts dentry->d_hash into
the hlist_bl bucket. If the dentry is already hashed, reinserting the
same node can corrupt the bucket, including creating a self-loop.
Once that happens, __d_lookup() can spin forever in the hlist_bl walk,
typically looping only on the d_name.hash mismatch check and
eventually triggering RCU stall reports like this one:
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 87-....: (2100 ticks this GP) idle=3a4c/1/0x4000000000000000 softirq=25003319/25003319 fqs=829
rcu: (t=2101 jiffies g=79058445 q=698988 ncpus=192)
CPU: 87 UID: 2952868916 PID: 3933303 Comm: php-cgi8.3 Not tainted 6.18.17-i1-amd #950 NONE
Hardware name: Dell Inc. PowerEdge R7615/0G9DHV, BIOS 1.6.6 09/22/2023
RIP: 0010:__d_lookup+0x46/0xb0
Code: c1 e8 07 48 8d 04 c2 48 8b 00 49 89 fc 49 89 f5 48 89 c3 48 83 e3 fe 48 83 f8 01 77 0f eb 2d 0f 1f 44 00 00 48 8b 1b 48 85 db <74> 20 39 6b 18 75 f3 48 8d 7b 78 e8 ba 85 d0 00 4c 39 63 10 74 1f
RSP: 0018:ff745a70c8253898 EFLAGS: 00000282
RAX: ff26e470054cb208 RBX: ff26e470054cb208 RCX: 000000006e958966
RDX: ff26e48267340000 RSI: ff745a70c82539b0 RDI: ff26e458f74655c0
RBP: 000000006e958966 R08: 0000000000000180 R09: 9cd08d909b919a89
R10: ff26e458f74655c0 R11: 0000000000000000 R12: ff26e458f74655c0
R13: ff745a70c82539b0 R14: d0d0d0d0d0d0d0d0 R15: 2f2f2f2f2f2f2f2f
FS: 00007f5770896980(0000) GS:ff26e482c5d88000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5764de50c0 CR3: 000000a72abb5001 CR4: 0000000000771ef0
PKRU: 55555554
Call Trace:
<TASK>
lookup_fast+0x9f/0x100
walk_component+0x1f/0x150
link_path_walk+0x20e/0x3d0
path_lookupat+0x68/0x180
filename_lookup+0xdc/0x1e0
vfs_statx+0x6c/0x140
vfs_fstatat+0x67/0xa0
__do_sys_newfstatat+0x24/0x60
do_syscall_64+0x6a/0x230
entry_SYSCALL_64_after_hwframe+0x76/0x7e
This is reachable with reused cached negative dentries. A Ceph lookup
or atomic_open can be handed a negative dentry that is already hashed,
and fs/ceph/dir.c then hits one of two paths that incorrectly assume
"negative" also means "unhashed":
- ceph_finish_lookup():
MDS reply is -ENOENT with no trace
-> d_add(dentry, NULL)
- ceph_lookup():
local ENOENT fast path for a complete directory with shared caps
-> d_add(dentry, NULL)
Both paths can therefore re-add an already-hashed negative dentry.
Ceph already uses the correct pattern elsewhere: ceph_fill_trace() only
calls d_add(dn, NULL) for a negative null-dentry reply when d_unhashed(dn)
is true.
Fix both fs/ceph/dir.c sites the same way: only call d_add() for a
negative dentry when it is actually unhashed. If the negative dentry
is already hashed, leave it in place and reuse it as-is.
This preserves the existing behavior for unhashed dentries while
avoiding d_hash list corruption for reused hashed negatives.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 2.6.34 | |
| linux | linux_kernel | 2.6.34 | |
| linux | linux_kernel | 2.6.34 | |
| linux | linux_kernel | 2.6.34 | |
| linux | linux_kernel | 2.6.34 | |
| linux | linux_kernel | 2.6.34 | |
| linux | linux_kernel | 2.6.34 |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ceph/dir.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "4147ae08824cc8b65d2b2018f79d416af2937108",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "73b47a1f06dee5e61b00dee5227d75d3f1f6d977",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "79ffcbeac6bc1dc1bcdb0434acf250f6215ec111",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "83ce43a21bb7df8dd52228afdd918d2d058eefde",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "4179cc390dacebc87079419ec92f86f3dc46294d",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "b91e535f208c48a5e7464f1aa38338a30e7912df",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "2010cb06b9df7d3c816c78358c566bdacbdf38ff",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
},
{
"lessThan": "803447f93d75ab6e40c85e6d12b5630d281d70d6",
"status": "affected",
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/ceph/dir.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.34"
},
{
"lessThan": "2.6.34",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.259",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.210",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.176",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.140",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.86",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.27",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "86294DD1-E89E-436E-80BC-95171A8D719F",
"versionEndExcluding": "6.6.140",
"versionStartIncluding": "2.6.34.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "55DA1C62-9991-451E-B8A8-E0004E00F789",
"versionEndExcluding": "6.12.86",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "A10AC84F-C058-47D5-85B4-E6E51A613B74",
"versionEndExcluding": "6.18.27",
"versionStartIncluding": "6.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "CDB78D6D-22C3-4154-B0D0-94AF1CE5C2E3",
"versionEndExcluding": "7.0.4",
"versionStartIncluding": "6.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:-:*:*:*:*:*:*",
"matchCriteriaId": "A3B1BC1D-ED46-4364-A1D9-1FA74182B03A",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:rc2:*:*:*:*:*:*",
"matchCriteriaId": "86D3F64C-3F27-43E0-B0D4-62CE1E1F4EFB",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:rc3:*:*:*:*:*:*",
"matchCriteriaId": "7927713B-5EB0-41EB-86A9-9935775162E0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:rc4:*:*:*:*:*:*",
"matchCriteriaId": "59037296-3143-4FBB-AFF7-D4FE2C85502F",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:rc5:*:*:*:*:*:*",
"matchCriteriaId": "9CA27FD5-7DBF-4C85-80A9-D523B2E4B033",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:rc6:*:*:*:*:*:*",
"matchCriteriaId": "9711E333-A8E7-4F4B-BCFD-2023E889651A",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.34:rc7:*:*:*:*:*:*",
"matchCriteriaId": "E04D3358-973B-42A1-8E08-2E3AE947193C",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: only d_add() negative dentries when they are unhashed\n\nCeph can call d_add(dentry, NULL) on a negative dentry that is already\npresent in the primary dcache hash.\n\nIn the current VFS that is not safe. d_add() goes through __d_add()\nto __d_rehash(), which unconditionally reinserts dentry-\u003ed_hash into\nthe hlist_bl bucket. If the dentry is already hashed, reinserting the\nsame node can corrupt the bucket, including creating a self-loop.\nOnce that happens, __d_lookup() can spin forever in the hlist_bl walk,\ntypically looping only on the d_name.hash mismatch check and\neventually triggering RCU stall reports like this one:\n\n rcu: INFO: rcu_sched self-detected stall on CPU\n rcu: 87-....: (2100 ticks this GP) idle=3a4c/1/0x4000000000000000 softirq=25003319/25003319 fqs=829\n rcu: (t=2101 jiffies g=79058445 q=698988 ncpus=192)\n CPU: 87 UID: 2952868916 PID: 3933303 Comm: php-cgi8.3 Not tainted 6.18.17-i1-amd #950 NONE\n Hardware name: Dell Inc. PowerEdge R7615/0G9DHV, BIOS 1.6.6 09/22/2023\n RIP: 0010:__d_lookup+0x46/0xb0\n Code: c1 e8 07 48 8d 04 c2 48 8b 00 49 89 fc 49 89 f5 48 89 c3 48 83 e3 fe 48 83 f8 01 77 0f eb 2d 0f 1f 44 00 00 48 8b 1b 48 85 db \u003c74\u003e 20 39 6b 18 75 f3 48 8d 7b 78 e8 ba 85 d0 00 4c 39 63 10 74 1f\n RSP: 0018:ff745a70c8253898 EFLAGS: 00000282\n RAX: ff26e470054cb208 RBX: ff26e470054cb208 RCX: 000000006e958966\n RDX: ff26e48267340000 RSI: ff745a70c82539b0 RDI: ff26e458f74655c0\n RBP: 000000006e958966 R08: 0000000000000180 R09: 9cd08d909b919a89\n R10: ff26e458f74655c0 R11: 0000000000000000 R12: ff26e458f74655c0\n R13: ff745a70c82539b0 R14: d0d0d0d0d0d0d0d0 R15: 2f2f2f2f2f2f2f2f\n FS: 00007f5770896980(0000) GS:ff26e482c5d88000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f5764de50c0 CR3: 000000a72abb5001 CR4: 0000000000771ef0\n PKRU: 55555554\n Call Trace:\n \u003cTASK\u003e\n lookup_fast+0x9f/0x100\n walk_component+0x1f/0x150\n link_path_walk+0x20e/0x3d0\n path_lookupat+0x68/0x180\n filename_lookup+0xdc/0x1e0\n vfs_statx+0x6c/0x140\n vfs_fstatat+0x67/0xa0\n __do_sys_newfstatat+0x24/0x60\n do_syscall_64+0x6a/0x230\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThis is reachable with reused cached negative dentries. A Ceph lookup\nor atomic_open can be handed a negative dentry that is already hashed,\nand fs/ceph/dir.c then hits one of two paths that incorrectly assume\n\"negative\" also means \"unhashed\":\n\n - ceph_finish_lookup():\n MDS reply is -ENOENT with no trace\n -\u003e d_add(dentry, NULL)\n\n - ceph_lookup():\n local ENOENT fast path for a complete directory with shared caps\n -\u003e d_add(dentry, NULL)\n\nBoth paths can therefore re-add an already-hashed negative dentry.\n\nCeph already uses the correct pattern elsewhere: ceph_fill_trace() only\ncalls d_add(dn, NULL) for a negative null-dentry reply when d_unhashed(dn)\nis true.\n\nFix both fs/ceph/dir.c sites the same way: only call d_add() for a\nnegative dentry when it is actually unhashed. If the negative dentry\nis already hashed, leave it in place and reuse it as-is.\n\nThis preserves the existing behavior for unhashed dentries while\navoiding d_hash list corruption for reused hashed negatives."
}
],
"id": "CVE-2026-46052",
"lastModified": "2026-06-19T13:16:32.420",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-05-27T14:17:24.807",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/2010cb06b9df7d3c816c78358c566bdacbdf38ff"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4147ae08824cc8b65d2b2018f79d416af2937108"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/4179cc390dacebc87079419ec92f86f3dc46294d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/73b47a1f06dee5e61b00dee5227d75d3f1f6d977"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/79ffcbeac6bc1dc1bcdb0434acf250f6215ec111"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/803447f93d75ab6e40c85e6d12b5630d281d70d6"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/83ce43a21bb7df8dd52228afdd918d2d058eefde"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/b91e535f208c48a5e7464f1aa38338a30e7912df"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "NVD-CWE-noinfo"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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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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