SB2026050275 - Out-of-bounds read in Linux kernel io_uring

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds read (CVE-ID: CVE-2026-31774)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in io_bundle_nbufs() when processing oversized sqe->len values through the io_uring bundle recv/send path. A local user can submit crafted io_uring requests to disclose sensitive information.

The issue is triggered by an integer overflow that turns a large __u32 length value into a negative int, which then propagates into an infinite loop that reads past allocated iovec entries.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1b655cd311344117d3052f6552cb20d9901c9d7c
• https://git.kernel.org/stable/c/90ced24c500ad4e129e9e34b7e56fd7849e350b6
• https://git.kernel.org/stable/c/b948f9d5d3057b01188e36664e7c7604d1c8ecb5
• https://git.kernel.org/stable/c/c314b405dcc4d8b9041124f928f81715d6328bec