CVE-2024-58000 in Linux
Summary
by MITRE • 02/27/2025
In the Linux kernel, the following vulnerability has been resolved:
io_uring: prevent reg-wait speculations
With *ENTER_EXT_ARG_REG instead of passing a user pointer with arguments for the waiting loop the user can specify an offset into a pre-mapped region of memory, in which case the [offset, offset + sizeof(io_uring_reg_wait)) will be intepreted as the
argument.
As we address a kernel array using a user given index, it'd be a subject to speculation type of exploits. Use array_index_nospec() to prevent that. Make sure to pass not the full region size but truncate by the maximum offset allowed considering the structure size.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/24/2026
The vulnerability CVE-2024-58000 resides within the Linux kernel's io_uring subsystem, specifically addressing a speculative execution flaw in the handling of register wait operations. This issue affects the kernel's io_uring implementation which provides high-performance asynchronous I/O capabilities for applications. The vulnerability manifests when using the ENTER_EXT_ARG_REG mechanism, which allows userspace applications to specify memory offsets within pre-mapped regions rather than passing direct user pointers to kernel memory locations.
The technical flaw stems from improper bounds checking when processing user-supplied indices that reference kernel arrays. When applications utilize the io_uring_register_wait() function with ENTER_EXT_ARG_REG, they can specify an offset into a pre-mapped memory region where the kernel expects to find argument data. The kernel then interprets a memory range starting at this user-provided offset and extending for the size of io_uring_reg_wait structure. This approach creates a potential speculative execution vulnerability because the kernel uses a user-provided index to access kernel arrays without proper bounds validation, making it susceptible to side-channel attacks and speculative execution exploits.
This vulnerability aligns with CWE-129, which addresses improper validation of array indices, and represents a classic example of a speculative execution flaw that can be exploited through cache timing attacks or similar side-channel techniques. The issue specifically targets the kernel's memory management and access control mechanisms, where user-provided data directly influences kernel memory access patterns. The exploitation potential is significant as it allows attackers to potentially bypass kernel memory protection mechanisms through speculative execution techniques that can infer information about kernel memory contents.
The operational impact of this vulnerability extends across all Linux systems running kernel versions that include the affected io_uring implementation, particularly impacting systems with high-performance I/O requirements where io_uring is actively used. Applications utilizing io_uring's register wait functionality with extended argument registration are at risk, potentially exposing the kernel to information disclosure attacks or privilege escalation scenarios. The vulnerability affects systems where kernel memory can be speculated upon through carefully crafted user-space inputs, making it particularly dangerous in multi-tenant environments or systems where untrusted applications might be executing.
The fix implemented addresses the vulnerability by incorporating array_index_nospec() function calls to prevent speculative execution attacks on kernel arrays. This mitigation ensures that user-provided indices are properly validated and constrained within safe bounds before being used to access kernel memory. The solution specifically truncates the memory region size to account for the maximum allowed offset based on the structure size, preventing attackers from specifying offsets that would access kernel memory beyond intended boundaries. This approach follows established security practices for preventing speculative execution vulnerabilities and aligns with ATT&CK technique T1068 by addressing privilege escalation paths through kernel memory manipulation. The patch effectively closes the attack surface by ensuring that kernel memory access patterns remain predictable and不受用户控制的输入影响，从而防止了通过缓存侧信道攻击获取敏感内核信息的可能性。