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CVE-2025-39793

HIGHCVSS 7.8/10EPSS 0.14%

Last modified

CVE-2025-39793 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.14% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.14%

3.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 6.14, < 6.15.11
LinuxLinux Kernel>= 6.16, < 6.16.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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.
How severe is CVE-2025-39793?
CVE-2025-39793 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.
How do I fix CVE-2025-39793?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-39793?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST