Vulnerability in Linux

CVE-2025-39793

In the Linux kernel, the following vulnerability has been resolved: io_uring/memmap: cast nr_pages to size_t before shifting If the allocated size exceeds UINT_MAX, then it's necessary to cast the mr->nr_pages value to size_t to prevent it from overflowing. In practice this isn't much of a concern as the required memory size will have been validated upfront, and accounted to the user. And > 4GB sizes will be necessary to make the lack of a cast a problem, which greatly exceeds normal user locked_vm settings that are generally in the kb to mb range. However, if root is used, then accounting isn't done, and then it's possible to hit this issue.

EPSS: 0.001 (3.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

References

Frequently asked questions

What is CVE-2025-39793?
CVE-2025-39793 is a high-severity vulnerability in Linux. CVSS score: 7.8/10. Published 2025-09-12.
How severe is CVE-2025-39793?
High severity. CVSS v3 base score is 7.8 out of 10.