Bug 2400061 (CVE-2025-39793) - CVE-2025-39793 kernel: io_uring/memmap: cast nr_pages to size_t before shifting
Summary: CVE-2025-39793 kernel: io_uring/memmap: cast nr_pages to size_t before shifting
Keywords:
Status: NEW
Alias: CVE-2025-39793
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-09-29 07:02 UTC by OSIDB Bzimport
Modified: 2025-09-29 18:06 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2025-09-29 07:02:15 UTC
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.


Note You need to log in before you can comment on or make changes to this bug.