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CVE-2025-21887 is a use-after-free flaw in Linux kernel OverlayFS. In the copy-up link path, ovl_link_up() released the upper dentry with dput() before ovl_dentry_update_reval() had completed using that dentry. The subsequent ovl_dentry_remote() call accessed upper->d_flags after the dentry could have been freed. The upstream correction defers dput(upper) until after its final use.
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Linux kernel OverlayFS use-after-free flaw in dentry revalidation.
A Linux kernel OverlayFS use-after-free vulnerability involving ovl_dentry_update_reval and ovl_link_up.
A use-after-free vulnerability in the Linux kernel OverlayFS implementation. During copy-up/link operations, OverlayFS could release an upper dentry with dput() before its final use by ovl_dentry_update_reval()/ovl_dentry_remote(), leading to access of freed memory.
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Cross-references every affected SKU, including bundled OEM variants.
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