CVE-2025-71203
Unknown Unknown - Not Provided

Speculative Execution Side-Channel in Linux riscv Syscall Handling

Vulnerability report for CVE-2025-71203, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-02-14

Last updated on: 2026-03-25

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: riscv: Sanitize syscall table indexing under speculation The syscall number is a user-controlled value used to index into the syscall table. Use array_index_nospec() to clamp this value after the bounds check to prevent speculative out-of-bounds access and subsequent data leakage via cache side channels.

CVSS Scores

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Meta Information

Published
2026-02-14
Last Modified
2026-03-25
Generated
2026-07-06
AI Q&A
2026-02-14
EPSS Evaluated
2026-07-05
NVD
EUVD

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel From 6.13 (inc) to 6.18.10 (exc)
linux linux_kernel From 6.4 (inc) to 6.12.70 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-129 The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

Attack-Flow Graph

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Executive Summary

This vulnerability exists in the Linux kernel on the RISC-V architecture. It involves the use of a user-controlled syscall number to index into the syscall table. Without proper sanitization, this can lead to speculative out-of-bounds access, which may allow data leakage through cache side channels. The fix involves using array_index_nospec() to clamp the syscall number after the bounds check, preventing speculative execution from accessing invalid memory locations.

Impact Analysis

This vulnerability can potentially allow an attacker to leak sensitive data from the kernel memory by exploiting speculative execution and cache side channels. Since the syscall number is user-controlled, an attacker could manipulate it to access data beyond the intended bounds, leading to unauthorized information disclosure.

Compliance Impact

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Detection Guidance

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Mitigation Strategies

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