CVE Catalog

CVE-2026-43442

High
Published: Translated: NVD NIST

Summary

A vulnerability has been identified in the Linux kernel related to the io_uring mechanism, concerning the bounds check for 128-byte SQE_MIXED operations. The flaw involved validating the logical position instead of the physical SQE index, potentially leading to unauthorized memory access.

Risk Assessment

This vulnerability could allow unprivileged users to remap logical positions to arbitrary physical indices, posing a risk of memory integrity breaches and potential execution of malicious code.

Recommendation

It is recommended to update the Linux kernel to the latest version that includes a fix for this vulnerability to secure the system against possible attacks.

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops When IORING_SETUP_SQE_MIXED is used without IORING_SETUP_NO_SQARRAY, the boundary check for 128-byte SQE operations in io_init_req() validated the logical SQ head position rather than the physical SQE index. The existing check: !(ctx->cached_sq_head & (ctx->sq_entries - 1)) ensures the logical position isn't at the end of the ring, which is correct for NO_SQARRAY rings where physical == logical. However, when sq_array is present, an unprivileged user can remap any logical position to an arbitrary physical index via sq_array. Setting sq_array[N] = sq_entries - 1 places a 128-byte operation at the last physical SQE slot, causing the 128-byte memcpy in io_uring_cmd_sqe_copy() to read 64 bytes past the end of the SQE array. Replace the cached_sq_head alignment check with a direct validation of the physical SQE index, which correctly handles both sq_

Vulnerability data from NVD (NIST) · CISA KEV · EPSS