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vuln-cve/data/2026/46xxx/CVE-2026-46052.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-46052",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-05-13T15:03:33.094Z",
"datePublished": "2026-05-27T12:57:10.777Z",
"dateUpdated": "2026-10-19T19:26:42.195Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-05T12:29:20.131Z"
},
"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->d_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 <74> 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 <TASK>\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 -> d_add(dentry, NULL)\n\n - ceph_lookup():\n local ENOENT fast path for a complete directory with shared caps\n -> 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."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"baseScore": 7.5,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - Ceph is a network filesystem client; the vulnerable `ceph_finish_lookup()` path is driven directly by remote MDS reply data (-ENOENT with no trace), so a malicious/compromised MDS or on-path attacker injecting crafted replies can drive the buggy `d_add()` on a hashed negative dentry. Processing remote-peer data places this at Network.\nAC:L - The corruption arose naturally in production from an ordinary `newfstatat`, showing the precondition (a reused already-hashed negative dentry) is reliably reachable; an attacker controlling MDS replies/lease grants can deterministically set up the cached negative dentry and re-lookup with no race outside their control.\nPR:N - A network attacker who controls or impersonates the MDS (or MITMs the unauthenticated msgr path) needs no privileges or credentials on the victim client to feed the -ENOENT-no-trace replies that trigger the vulnerable code.\nUI:N - On an established Ceph mount, path lookups/stats occur continuously as part of normal operation, so no specific victim action is required at exploit time.\nS:U - The corruption and resulting hang are entirely within the kernel's own dcache; no security boundary (VM, IOMMU, sandbox) is crossed.\nC:N - The bug creates a self-referential cycle in an hlist_bl hash bucket and leaks no memory contents; there is no out-of-bounds or use-after-free read primitive.\nI:N - The only state altered is an internal dcache list pointer forming a loop; this provides no attacker-controllable write primitive and modifies no user or security-relevant data.\nA:H - `__d_lookup()` spins forever on the corrupted bucket, producing RCU stalls and a hung/softlocked CPU — a kernel-level denial of service."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/ceph/dir.c"
],
"versions": [
{
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"lessThan": "4147ae08824cc8b65d2b2018f79d416af2937108",
"status": "affected",
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},
{
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"status": "affected",
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{
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"lessThan": "2010cb06b9df7d3c816c78358c566bdacbdf38ff",
"status": "affected",
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},
{
"version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef",
"lessThan": "803447f93d75ab6e40c85e6d12b5630d281d70d6",
"status": "affected",
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}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/ceph/dir.c"
],
"versions": [
{
"version": "2.6.34",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.34",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.10.259",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "5.15.210",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.1.176",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.6.140",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.86",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.27",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.0.4",
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.1",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.34",
"versionEndExcluding": "5.10.259"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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}
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"references": [
{
"url": "https://git.kernel.org/stable/c/4147ae08824cc8b65d2b2018f79d416af2937108"
},
{
"url": "https://git.kernel.org/stable/c/73b47a1f06dee5e61b00dee5227d75d3f1f6d977"
},
{
"url": "https://git.kernel.org/stable/c/79ffcbeac6bc1dc1bcdb0434acf250f6215ec111"
},
{
"url": "https://git.kernel.org/stable/c/83ce43a21bb7df8dd52228afdd918d2d058eefde"
},
{
"url": "https://git.kernel.org/stable/c/4179cc390dacebc87079419ec92f86f3dc46294d"
},
{
"url": "https://git.kernel.org/stable/c/b91e535f208c48a5e7464f1aa38338a30e7912df"
},
{
"url": "https://git.kernel.org/stable/c/2010cb06b9df7d3c816c78358c566bdacbdf38ff"
},
{
"url": "https://git.kernel.org/stable/c/803447f93d75ab6e40c85e6d12b5630d281d70d6"
}
],
"title": "ceph: only d_add() negative dentries when they are unhashed",
"x_generator": {
"engine": "bippy-1.2.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"id": "CVE-2026-46052",
"role": "CISA Coordinator",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-10-16T15:19:14.236187Z"
}
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"type": "CWE",
"cweId": "CWE-835",
"description": "CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')"
}
]
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-10-19T19:26:42.195Z"
}
}
]
}
}