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vuln-cve/data/2026/45xxx/CVE-2026-45955.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-45955",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-05-13T15:03:33.088Z",
"datePublished": "2026-05-27T12:18:10.951Z",
"dateUpdated": "2026-10-19T19:26:40.445Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-05T12:28:54.212Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd/md-llbitmap: fix percpu_ref not resurrected on suspend timeout\n\nWhen llbitmap_suspend_timeout() times out waiting for percpu_ref to\nbecome zero, it returns -ETIMEDOUT without resurrecting the percpu_ref.\nThe caller (md_llbitmap_daemon_fn) then continues to the next page\nwithout calling llbitmap_resume(), leaving the percpu_ref in a killed\nstate permanently.\n\nFix this by resurrecting the percpu_ref before returning the error,\nensuring the page control structure remains usable for subsequent\noperations."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
"baseScore": 7.1,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The flaw is in the MD lockless bitmap (`md-llbitmap`), reached only from the block/MD write path (`md_bitmap_start` → `llbitmap_start_write`), not from a network protocol handler. Any remote party must already cause writes through local VFS/block access (e.g., a file on an md-backed volume).\nAC:L - On a system with llbitmap enabled, an attacker can reliably force the timeout by racing the periodic daemon against many concurrent writes to the same bitmap page that hold `percpu_ref` until `daemon_sleep` expires; both sides of the race are attacker-driven I/O patterns.\nPR:L - Exploitation does not require real root in the init namespace: any principal that can issue writes to storage backed by an affected md array (typical unprivileged user on a multi-tenant NAS, or a member of the `disk` group with raw `/dev/md*` access) reaches the vulnerable code.\nUI:N - Triggering the race requires only sustained automated write I/O; no victim click, mount dialog, or other interactive action is needed beyond normal storage use.\nS:U - Impact stays within kernel/MD RAID scope (hang and bitmap inconsistency on the host); it does not cross a VM, container, or IOMMU security boundary.\nC:N - This is a refcount lifecycle logic bug, not memory corruption; there is no out-of-bounds access, UAF, or other primitive that discloses kernel memory.\nI:H - After the bug, `llbitmap_raise_barrier()` can block new writes before `llbitmap_state_machine()` runs, so dirty regions may not be recorded; combined with uncleared dirty bits on other paths, RAID resync decisions can be wrong after crash—high integrity risk for redundant storage.\nA:H - A permanently killed `percpu_ref` leaves writers stuck in uninterruptible `wait_event` in `llbitmap_raise_barrier()`, causing indefinite write hangs (effective DoS) for affected bitmap pages on production NAS/RAID systems."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/md/md-llbitmap.c"
],
"versions": [
{
"version": "5ab829f1971dc99f2aac10846c378e67fc875abc",
"lessThan": "095417d6b669c2dec39a5842ccb94df915f97f54",
"status": "affected",
"versionType": "git"
},
{
"version": "5ab829f1971dc99f2aac10846c378e67fc875abc",
"lessThan": "2446d099350185caeed19ab2c0270451a97296fb",
"status": "affected",
"versionType": "git"
},
{
"version": "5ab829f1971dc99f2aac10846c378e67fc875abc",
"lessThan": "d119bd2e1643cc023210ff3c6f0657e4f914e71d",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/md/md-llbitmap.c"
],
"versions": [
{
"version": "6.18",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.18",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.14",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.19.4",
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.0",
"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": "6.18",
"versionEndExcluding": "6.18.14"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.18",
"versionEndExcluding": "6.19.4"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.18",
"versionEndExcluding": "7.0"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/095417d6b669c2dec39a5842ccb94df915f97f54"
},
{
"url": "https://git.kernel.org/stable/c/2446d099350185caeed19ab2c0270451a97296fb"
},
{
"url": "https://git.kernel.org/stable/c/d119bd2e1643cc023210ff3c6f0657e4f914e71d"
}
],
"title": "md/md-llbitmap: fix percpu_ref not resurrected on suspend timeout",
"x_generator": {
"engine": "bippy-1.2.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"id": "CVE-2026-45955",
"role": "CISA Coordinator",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-10-16T15:18:35.481520Z"
}
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"type": "CWE",
"cweId": "CWE-404",
"description": "CWE-404 Improper Resource Shutdown or Release"
}
]
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-10-19T19:26:40.445Z"
}
}
]
}
}