CVE-2026-46315: io_uring/waitid: clear waitid info before copying it to userspace

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-09 · updated 2026-07-23

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/waitid: clear waitid info before copying it to userspace IORING_OP_WAITID stores its result fields in struct io_waitid::info and later copies them to userspace siginfo. The prep path initializes the request arguments, but it does not initialize info itself. If the wait operation completes without reporting a child event, the common wait code can return without writing wo_info. In that case io_waitid_finish() still copies iw->info to userspace, exposing stale bytes from the reused io_kiocb command storage. Clear the result storage during prep so the io_uring path matches the regular waitid syscall, which uses a zero-initialized struct waitid_info.

Affected products

Linux kernel: from 6.7 before 6.12.92; from 6.13 before 6.18.34; from 6.19 before 7.0.11; 7.1-rc1, 7.1-rc2, 7.1-rc3, 7.1-rc4 — fixed in 6.12.92, 6.18.34, 7.0.11

How to fix

Upgrade to a fixed version: Linux kernel 6.12.92, 6.18.34, 7.0.11. Check the vendor advisory for mitigations.

References

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