CVE-2026-23275High· 7.8▾ Twilight

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

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,…

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 42.9 · likelihood 0 · exploitation 0

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Proof of concept

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Published

Mar 20, 2026

Updated

Oct 19, 2026

CVSS

7.8

Vendor

Linux

Product

Linux

CWE

—

Depth score

43 · Moderate

EPSS

0.10% · p1

Platforms

—

Source

CVEORG

Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

decided 2026-10-16

Exploitation: none
Automatable: no
Technical impact: total

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.

EPSS history

Exploit-prediction probability, daily snapshots since Oct 16.

0.1% → 0.10%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

4 events · 213 days

Mar 20, 2026Published
Disclosed via CVEORG
Oct 16, 2026EPSS first tracked
0.1%
Oct 17, 2026EPSS peak
0.1% → 0.1%
Oct 19, 2026Record revised
Last analysed / modified upstream

Linux #cve.org

Affected

Linux >= 79cfe9e59c2a12c3b3faeeefe38d23f3d8030972 < 7cc4530b3e952d4a5947e1e55d06620d8845d4f5
Linux >= 79cfe9e59c2a12c3b3faeeefe38d23f3d8030972 < 46dc07d5f31411cc023f3bf1f4a23a07bf6e0ed1
Linux >= 79cfe9e59c2a12c3b3faeeefe38d23f3d8030972 < 96189080265e6bb5dde3a4afbaf947af493e3f82
Linux 6.13

Full technical detail▾

Overview

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.

Affected

Linux >= 79cfe9e59c2a12c3b3faeeefe38d23f3d8030972 < 7cc4530b3e952d4a5947e1e55d06620d8845d4f5
Linux >= 79cfe9e59c2a12c3b3faeeefe38d23f3d8030972 < 46dc07d5f31411cc023f3bf1f4a23a07bf6e0ed1
Linux >= 79cfe9e59c2a12c3b3faeeefe38d23f3d8030972 < 96189080265e6bb5dde3a4afbaf947af493e3f82
Linux 6.13

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#cve.org

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

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 42.9 · likelihood 0 · exploitation 0

Overview

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

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

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.