{
    "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": "2026-08-05T12:28:54.212Z"
    },
    "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": [
                        {
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                            "negate": false,
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                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                                    "versionEndExcluding": "6.18.14"
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                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/095417d6b669c2dec39a5842ccb94df915f97f54"
                },
                {
                    "url": "https://git.kernel.org/stable/c/2446d099350185caeed19ab2c0270451a97296fb"
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                {
                    "url": "https://git.kernel.org/stable/c/d119bd2e1643cc023210ff3c6f0657e4f914e71d"
                }
            ],
            "title": "md/md-llbitmap: fix percpu_ref not resurrected on suspend timeout",
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}