Riskcovery

CVE-2026-81009

io_uring/query: cap user size passed to copy_struct_to_user

State
Published
Severity
Not scored
Published
Sep 11, 2026
Updated
Oct 19, 2026
Reserved
Aug 26, 2026

Read the record on cve.org

Description

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

io_uring/query: cap user size passed to copy_struct_to_user

io_handle_query_entry() clamps hdr.size for the inbound copy_from_user() but keeps the original user value as usize. copy_struct_to_user() uses that usize and, when it is larger than the kernel result, clear_user()s the trailing bytes.

As hdr.size is a __u32, a query can request nearly 4 GiB of zeroing, including on the error path where res_size stays 0. The interface is reachable without a ring via IORING_REGISTER_QUERY.

Reject sizes larger than PAGE_SIZE, as recommended for copy_struct_* interfaces.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • c265ae75f900cea4e415230a77b5d152377627dd to before 417e02f7b6051765b91cf1289071882eebd172e0Affected
  • c265ae75f900cea4e415230a77b5d152377627dd to before 2b8ad4981ecedb14c1fdd811ab977010b23933e6Affected
  • c265ae75f900cea4e415230a77b5d152377627dd to before ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95bAffected
LinuxLinux
  • 6.18Affected
  • before 6.18Not affected
  • 6.18.50 through 6.18.*Not affected
  • 7.2.4 through 7.2.*Not affected
  • 7.3 and laterNot affected

References

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