CVE-2026-46274 (GCVE-0-2026-46274)
Vulnerability from cvelistv5 – Published: 2026-06-08 14:30 – Updated: 2026-06-14 18:05
VLAI
Title
io-wq: check that the predecessor is hashed in io_wq_remove_pending()
Summary
In the Linux kernel, the following vulnerability has been resolved:
io-wq: check that the predecessor is hashed in io_wq_remove_pending()
io_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled
work was the tail of its hash bucket. When doing this, it checks whether
the preceding entry in acct->work_list has the same hash value, but
never checks that the predecessor is hashed at all. io_get_work_hash()
is simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash
bits are never set for non-hashed work, so it returns 0. Thus, when a
hashed bucket-0 work is cancelled while a non-hashed work is its list
predecessor, the check spuriously passes and a pointer to the non-hashed
io_kiocb is stored in wq->hash_tail[0].
Because non-hashed work is dequeued via the fast path in
io_get_next_work(), which never touches hash_tail[], the stale pointer
is never cleared. Therefore, after the non-hashed io_kiocb completes and
is freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The
io_wq is per-task (tctx->io_wq) and survives ring open/close, so the
dangling pointer persists for the lifetime of the task; the next hashed
bucket-0 enqueue dereferences it in io_wq_insert_work() and
wq_list_add_after() writes through freed memory.
Add the missing io_wq_is_hashed() check so a non-hashed predecessor
never inherits a hash_tail[] slot.
Severity
7.8 (High)
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
204361a77f4018627addd4a06877448f088ddfc0 , < d6bda9df0c0a3080804181464d5c0f4d78a4e769
(git)
Affected: 204361a77f4018627addd4a06877448f088ddfc0 , < 5a20ebf0c81b61f5ea3b1b529c100cad69b9f603 (git) Affected: 204361a77f4018627addd4a06877448f088ddfc0 , < 252c5051dba9c709b6a72f2866f93e5e618b3f06 (git) Affected: 204361a77f4018627addd4a06877448f088ddfc0 , < d376c131af7c7739a87ff037ed2fdb67c2542c8a (git) Affected: 204361a77f4018627addd4a06877448f088ddfc0 , < d6a2d7b04b5a093021a7a0e2e69e9d5237dfa8cc (git) Affected: 13f35a2c0fd5c6a4fcd8903542b053bcc914fcf5 (git) Affected: 5.8.6 , < 5.9 (semver) |
|
| Linux | Linux |
Affected:
5.9
Unaffected: 0 , < 5.9 (semver) Unaffected: 6.6.141 , ≤ 6.6.* (semver) Unaffected: 6.12.91 , ≤ 6.12.* (semver) Unaffected: 6.18.33 , ≤ 6.18.* (semver) Unaffected: 7.0.10 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix) |
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"version": "6.18.33",
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},
{
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"status": "unaffected",
"version": "7.0.10",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
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}
],
"cpeApplicability": [
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio-wq: check that the predecessor is hashed in io_wq_remove_pending()\n\nio_wq_remove_pending() needs to fix up wq-\u003ehash_tail[] if the cancelled\nwork was the tail of its hash bucket. When doing this, it checks whether\nthe preceding entry in acct-\u003ework_list has the same hash value, but\nnever checks that the predecessor is hashed at all. io_get_work_hash()\nis simply atomic_read(\u0026work-\u003eflags) \u003e\u003e IO_WQ_HASH_SHIFT, and the hash\nbits are never set for non-hashed work, so it returns 0. Thus, when a\nhashed bucket-0 work is cancelled while a non-hashed work is its list\npredecessor, the check spuriously passes and a pointer to the non-hashed\nio_kiocb is stored in wq-\u003ehash_tail[0].\n\nBecause non-hashed work is dequeued via the fast path in\nio_get_next_work(), which never touches hash_tail[], the stale pointer\nis never cleared. Therefore, after the non-hashed io_kiocb completes and\nis freed back to req_cachep, wq-\u003ehash_tail[0] is a dangling pointer. The\nio_wq is per-task (tctx-\u003eio_wq) and survives ring open/close, so the\ndangling pointer persists for the lifetime of the task; the next hashed\nbucket-0 enqueue dereferences it in io_wq_insert_work() and\nwq_list_add_after() writes through freed memory.\n\nAdd the missing io_wq_is_hashed() check so a non-hashed predecessor\nnever inherits a hash_tail[] slot."
}
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"providerMetadata": {
"dateUpdated": "2026-06-14T18:05:34.336Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"cveId": "CVE-2026-46274",
"datePublished": "2026-06-08T14:30:53.323Z",
"dateReserved": "2026-05-13T15:03:33.109Z",
"dateUpdated": "2026-06-14T18:05:34.336Z",
"state": "PUBLISHED"
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}
}
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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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