Bug 2378985 (CVE-2025-38247)

Summary: CVE-2025-38247 kernel: userns and mnt_idmap leak in open_tree_attr(2)
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-07-09 11:01:50 UTC 
In the Linux kernel, the following vulnerability has been resolved:

userns and mnt_idmap leak in open_tree_attr(2)

Once want_mount_setattr() has returned a positive, it does require
finish_mount_kattr() to release ->mnt_userns.  Failing do_mount_setattr()
does not change that.

As the result, we can end up leaking userns and possibly mnt_idmap as
well.
Comment 1 Jon Moroney 2025-07-09 17:48:33 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025070934-CVE-2025-38247-14ac@gregkh/T