In the Linux kernel, the following vulnerability has been resolved:

io_uring: ensure ctx->rings is stable for task work flags manipulation

If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while
the ring is being resized, it's possible for the OR'ing of
IORING_SQ_TASKRUN to happen in the small window of swapping into the
new rings and the old rings being freed.

Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is
protected by RCU. The task work flags manipulation is inside RCU
already, and if the resize ring freeing is done post an RCU synchronize,
then there's no need to add locking to the fast path of task work
additions.

Note: this is only done for DEFER_TASKRUN, as that's the only setup mode
that supports ring resizing. If this ever changes, then they too need to
use the io_ctx_mark_taskrun() helper.

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History

Fri, 20 Mar 2026 10:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Fri, 20 Mar 2026 08:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: io_uring: ensure ctx->rings is stable for task work flags manipulation If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while the ring is being resized, it's possible for the OR'ing of IORING_SQ_TASKRUN to happen in the small window of swapping into the new rings and the old rings being freed. Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is protected by RCU. The task work flags manipulation is inside RCU already, and if the resize ring freeing is done post an RCU synchronize, then there's no need to add locking to the fast path of task work additions. Note: this is only done for DEFER_TASKRUN, as that's the only setup mode that supports ring resizing. If this ever changes, then they too need to use the io_ctx_mark_taskrun() helper.
Title io_uring: ensure ctx->rings is stable for task work flags manipulation
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-03-20T08:08:55.857Z

Reserved: 2026-01-13T15:37:45.991Z

Link: CVE-2026-23275

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-20T09:16:13.223

Modified: 2026-03-20T09:16:13.223

Link: CVE-2026-23275

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-03-20T10:36:44Z

Weaknesses