CVE-2026-43408
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ceph: add a bunch of missing ceph_path_info initializers ceph_mdsc_build_path() must be called with a zero-initialized ceph_path_info parameter, or else the following ceph_mdsc_free_path_info() may crash. Example crash (on Linux 6.18.12): virt_to_cache: Object is not a Slab page! WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6732 kmem_cache_free+0x316/0x400 [...] Call Trace: [...] ceph_open+0x13d/0x3e0 do_dentry_open+0x134/0x480 vfs_open+0x2a/0xe0 path_openat+0x9a3/0x1160 [...] cache_from_obj: Wrong slab cache. names_cache but object is from ceph_inode_info WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6746 kmem_cache_free+0x2dd/0x400 [...] kernel BUG at mm/slub.c:634! Oops: invalid opcode: 0000 [#1] SMP NOPTI RIP: 0010:__slab_free+0x1a4/0x350 Some of the ceph_mdsc_build_path() callers had initializers, but others had not, even though they were all added by commit 15f519e9f883 ("ceph: fix race condition validating r_parent before applying state"). The ones without initializer are suspectible to random crashes. (I can imagine it could even be possible to exploit this bug to elevate privileges.) Unfortunately, these Ceph functions are undocumented and its semantics can only be derived from the code. I see that ceph_mdsc_build_path() initializes the structure only on success, but not on error. Calling ceph_mdsc_free_path_info() after a failed ceph_mdsc_build_path() call does not even make sense, but that's what all callers do, and for it to be safe, the structure must be zero-initialized. The least intrusive approach to fix this is therefore to add initializers everywhere.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-05-08 15:16:52.397000
Last modified
2026-10-21 13:18:56.273000
View original CVE JSON
{
"id": "CVE-2026-43408",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-05-08T15:16:52.397",
"lastModified": "2026-10-21T13:18:56.273",
"vulnStatus": "Modified",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: add a bunch of missing ceph_path_info initializers\n\nceph_mdsc_build_path() must be called with a zero-initialized\nceph_path_info parameter, or else the following\nceph_mdsc_free_path_info() may crash.\n\nExample crash (on Linux 6.18.12):\n\n virt_to_cache: Object is not a Slab page!\n WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6732 kmem_cache_free+0x316/0x400\n [...]\n Call Trace:\n [...]\n ceph_open+0x13d/0x3e0\n do_dentry_open+0x134/0x480\n vfs_open+0x2a/0xe0\n path_openat+0x9a3/0x1160\n [...]\n cache_from_obj: Wrong slab cache. names_cache but object is from ceph_inode_info\n WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6746 kmem_cache_free+0x2dd/0x400\n [...]\n kernel BUG at mm/slub.c:634!\n Oops: invalid opcode: 0000 [#1] SMP NOPTI\n RIP: 0010:__slab_free+0x1a4/0x350\n\nSome of the ceph_mdsc_build_path() callers had initializers, but\nothers had not, even though they were all added by commit 15f519e9f883\n(\"ceph: fix race condition validating r_parent before applying state\").\nThe ones without initializer are suspectible to random crashes. (I can\nimagine it could even be possible to exploit this bug to elevate\nprivileges.)\n\nUnfortunately, these Ceph functions are undocumented and its semantics\ncan only be derived from the code. I see that ceph_mdsc_build_path()\ninitializes the structure only on success, but not on error.\n\nCalling ceph_mdsc_free_path_info() after a failed\nceph_mdsc_build_path() call does not even make sense, but that's what\nall callers do, and for it to be safe, the structure must be\nzero-initialized. The least intrusive approach to fix this is\ntherefore to add initializers everywhere."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"fs/ceph/debugfs.c",
"fs/ceph/dir.c",
"fs/ceph/file.c",
"fs/ceph/inode.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "db378e6f83ec705c6091c65d482d555edc2b0a72",
"lessThan": "644b47f0574fd82aeb9d00317eca8d1f2a525c8c",
"versionType": "git",
"status": "affected"
},
{
"version": "15f519e9f883b316d86e2bb6b767a023aafd9d83",
"lessThan": "8be8911f590813e6f90bc6407ced1b23e50bc5da",
"versionType": "git",
"status": "affected"
},
{
"version": "15f519e9f883b316d86e2bb6b767a023aafd9d83",
"lessThan": "453df1f4535842bf17ff1885a225e153d7ee3374",
"versionType": "git",
"status": "affected"
},
{
"version": "15f519e9f883b316d86e2bb6b767a023aafd9d83",
"lessThan": "43323a5934b660afae687e8e4e95ac328615a5c4",
"versionType": "git",
"status": "affected"
},
{
"version": "dc5aad078abc416dd3d555c50f5308c16ba918a7",
"versionType": "git",
"status": "affected"
},
{
"version": "2bfe45987eb346e299d9f763f9cd05f77011519f",
"versionType": "git",
"status": "affected"
},
{
"version": "6.12.48",
"lessThan": "6.12.78",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.6.160",
"lessThan": "6.7",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.16.8",
"lessThan": "6.17",
"versionType": "semver",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"fs/ceph/debugfs.c",
"fs/ceph/dir.c",
"fs/ceph/file.c",
"fs/ceph/inode.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.17",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.17",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.78",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.19",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.19.9",
"lessThanOrEqual": "6.19.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.0",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-16T15:17:15.370750Z",
"id": "CVE-2026-43408",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Primary",
"description": [
{
"lang": "en",
"value": "CWE-476"
}
]
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-457"
}
]
}
],
"configurations": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.12.48",
"versionEndExcluding": "6.12.78",
"matchCriteriaId": "6EC06A5F-045A-48FD-8863-E8AB8E92B0BE"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.16.8",
"versionEndExcluding": "6.17",
"matchCriteriaId": "8C0D11FE-A1CB-4D09-B221-8281514EB44E"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.17.1",
"versionEndExcluding": "6.18.19",
"matchCriteriaId": "2B44FFCD-31AB-4CB4-8733-63F887DA5E89"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.19",
"versionEndExcluding": "6.19.9",
"matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:-:*:*:*:*:*:*",
"matchCriteriaId": "7CC8B11D-82DC-4958-8DC7-BF5CC829A5E9"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*",
"matchCriteriaId": "5A4516A6-C12E-42A4-8C0E-68AEF3264504"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc7:*:*:*:*:*:*",
"matchCriteriaId": "3963C3A0-CEA1-4F5C-8011-3A593ABB684D"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
"matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
"matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
"matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/43323a5934b660afae687e8e4e95ac328615a5c4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
]
},
{
"url": "https://git.kernel.org/stable/c/453df1f4535842bf17ff1885a225e153d7ee3374",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
]
},
{
"url": "https://git.kernel.org/stable/c/644b47f0574fd82aeb9d00317eca8d1f2a525c8c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
]
},
{
"url": "https://git.kernel.org/stable/c/8be8911f590813e6f90bc6407ced1b23e50bc5da",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
]
}
]
}