What’s Vulnerable › Vulnerabilities

CVE-2025-40291: io_uring: fix regbuf vector size truncation

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-08 · updated 2026-10-14

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix regbuf vector size truncation There is a report of io_estimate_bvec_size() truncating the calculated number of segments that leads to corruption issues. Check it doesn't overflow "int"s used later. Rough but simple, can be improved on top.

Affected products

• Linux kernel: 6.15 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/146eb58629f45f8297e83d69e64d4eea4b28d972
• https://git.kernel.org/stable/c/826ce37a842633efe1bb763e4b13045d74060d72

Get alerted when CVE-2025-40291 or the next vulnerability affects your stack