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Unrated severityNVD Advisory· Published Jul 12, 2024· Updated Nov 3, 2025

cachefiles: defer exposing anon_fd until after copy_to_user() succeeds

CVE-2024-40913

Description

In the Linux kernel, the following vulnerability has been resolved:

cachefiles: defer exposing anon_fd until after copy_to_user() succeeds

After installing the anonymous fd, we can now see it in userland and close it. However, at this point we may not have gotten the reference count of the cache, but we will put it during colse fd, so this may cause a cache UAF.

So grab the cache reference count before fd_install(). In addition, by kernel convention, fd is taken over by the user land after fd_install(), and the kernel should not call close_fd() after that, i.e., it should call fd_install() after everything is ready, thus fd_install() is called after copy_to_user() succeeds.

Affected products

50

Patches

4
d2d3eb377a5d
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
eac51d9daacd
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
4b4391e77a6b
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
b9f58cdae6a3
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit

Vulnerability mechanics

Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

4

News mentions

0

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