CVE-2026-98921
Published Oct 23, 2026
Description
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.
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References
Frequently Asked Questions
What is CVE-2026-98921? +
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.
How do I check if I'm vulnerable to CVE-2026-98921? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.