What’s Vulnerable › Vulnerabilities

CVE-2025-21863: io_uring: prevent opcode speculation

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-03-12 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring: prevent opcode speculation sqe->opcode is used for different tables, make sure we santitise it against speculations.

Affected products

• Linux kernel: from 5.6 before 6.6.80; from 6.7 before 6.12.17; from 6.13 before 6.13.5; 6.14-rc1, 6.14-rc2, 6.14-rc3 — fixed in 6.12.17, 6.13.5, 6.6.80

How to fix

Upgrade to a fixed version: Linux kernel 6.12.17, 6.13.5, 6.6.80. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/18eae8420081ef8e043ad455937bfb470ef08607
• https://git.kernel.org/stable/c/1e988c3fe1264708f4f92109203ac5b1d65de50b
• https://git.kernel.org/stable/c/506b9b5e8c2d2a411ea8fe361333f5081c56d23a
• https://git.kernel.org/stable/c/87e9eef43c758da267f6332678058a79764c7eba
• https://git.kernel.org/stable/c/b9826e3b26ec031e9063f64a7c735449c43955e4
• https://git.kernel.org/stable/c/d261ead565a080e3411b0dd04e6d58a52471cac8
• https://git.kernel.org/stable/c/fdbfd52bd8b85ed6783365ff54c82ab7067bd61b
• https://cert-portal.siemens.com/productcert/html/ssa-019113.html
• https://cert-portal.siemens.com/productcert/html/ssa-457936.html
• https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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