CVE-2026-46274 | io-wq: check that the predecessor is hashed in io_wq_remove_pending()

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.

Published: 2026-06-08 Last update: 2026-06-17 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Received，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-46274 is rated Low Risk (32.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.14%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-46274

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.14% +0.12%
2 2026-06-09 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-46274

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Weakness enumeration for CVE-2026-46274

GitHub Security Advisory for CVE-2026-46274

GHSA-52w9-98q8-6pwf · Severity: high — In the Linux kernel, the following vulnerability has been resolved: io-wq: check that the...

OS Trackers for CVE-2026-46274

vendor priority summary link
debian not yet assigned CVE-2026-46274 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2026-46274
redhat medium — https://access.redhat.com/security/cve/CVE-2026-46274
suse medium CVE-2026-46274 severity moderate: SUSE including 21 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 199 product×package rows across 40 product lines (SUSE Linux Enterprise High Availability Extension 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (40 product lines)): Known Not Affected 199. https://www.suse.com/security/cve/CVE-2026-46274/
ubuntu high CVE-2026-46274 high priority: Ubuntu including 162 source packages (linux, linux-allwinner-5.19, …), 1458 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1051, ignored 172, released 88, needed 76, not-affected 45, pending 26. https://ubuntu.com/security/CVE-2026-46274

Affected software / configurations for CVE-2026-46274

Vendor Product Version Raw CPE
linux linux_kernel >= 5.9, < 6.6.141 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.9, < 6.12.91 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.9, < 6.18.33 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.9, < 7.0.10 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.9, < 7.1 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.8.6 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

References for CVE-2026-46274

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