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CVE-2025-39793

7.8 · HIGH

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 th…

Published Sep 12, 2025EPSS 0.15%

Overview

CVE-2025-39793 is a high-severity vulnerability. It was published on September 12, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/33503c083fda048c77903460ac0429e1e2c0e341Refgit.kernel.org/stable/c/a69a9b53c54e2d33e2a5b1ea4a9a71fd01c6cf3aRefgit.kernel.org/stable/c/c6a2706e08b8a1b2d3740161c0977d38e596c1ee

How CyberStrike helps

Frequently asked questions

What is CVE-2025-39793?

CVE-2025-39793 is a high-severity vulnerability. It was published on September 12, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-39793?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2025-39793?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2025-39793?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2025-39793 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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