Bug 2559653 (CVE-2026-98921) - CVE-2026-98921 kernel: ovl: fix UAF in ovl_do_mkdir() debug print
Summary: CVE-2026-98921 kernel: ovl: fix UAF in ovl_do_mkdir() debug print
Keywords:
Status: NEW
Alias: CVE-2026-98921
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: 2026-10-23 12:52 UTC by OSIDB Bzimport
Modified: 2026-10-27 11:28 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-10-23 12:52:59 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ovl: fix UAF in ovl_do_mkdir() debug print

ovl_do_mkdir() prints the input dentry with %pd after vfs_mkdir().
Since commit fe497f0759e0 ("VFS: change vfs_mkdir() to unlock on
failure."), vfs_mkdir() calls end_creating() on the input dentry on
failure and may replace it on success, so the post-call %pd can
use-after-free the dentry when CONFIG_OVERLAY_FS_DEBUG is enabled.

Print the dentry before the call and only the result afterward.
Comment 1 Mauro Matteo Cascella 2026-10-27 11:21:40 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98921.mbox
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