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Review reviewHigh

CVE-2025-39793

Linux Linux, linux kernel

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...

CVSS
7.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2025.09.13
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.8

Vulnerability overview

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...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 087f997870a948820ec366701d178f402c6a23a3 < c6a2706e08b8a1b2d3740161c0977d38e596c1ee, >= 087f997870a948820ec366701d178f402c6a23a3 < a69a9b53c54e2d33e2a5b1ea4a9a71fd01c6cf3a, >= 087f997870a948820ec366701d178f402c6a23a3 < 33503c083fda048c77903460ac0429e1e2c0e341, >= 6.14, >= 6.14 < 6.15.11, >= 6.16 < 6.16.2
Fixed versions
6.15.11, 6.16.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available