CVE-2026-97594 — landlock: Fix use-after-free of the source's parent directory

Affected: Linux

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

landlock: Fix use-after-free of the source's parent directory

current_check_refer_path() reads old_dentry->d_parent without holding a reference nor a lock on it, and then dereferences it in collect_domain_accesses() and in the audit record.

A reference on a child does not pin its parent: __d_move() reassigns dentry->d_parent and drops the reference the child held on its former parent. hook_path_rename() is not affected because the rename path calls lock_rename() before the hook, so the source cannot be reparented under it. hook_path_link() has no such protection: filename_linkat() holds a reference on the source dentry but neither locks nor references its parent, so a concurrent rename(2) can reparent the source while security_path_link() runs, and the former parent can then be removed and freed while the hook walks it.

A process can trigger this after entering a Landlock domain that handles at least one filesystem access right. The process can then race a linkat(2) loop against rename(2) and rmdir(2):

BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290 Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549 collect_domain_accesses+0x278/0x290 current_check_refer_path+0x952/0x1120 security_path_link+0x1be/0x320 filename_linkat+0x342/0x6d0 __x64_sys_linkat+0xfa/0x150 Freed by task 562: kmem_cache_free+0x139/0x4c0 i_callback+0x4b/0x80 rcu_core+0x7dc…

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CVE-2026-97594 — landlock: Fix use-after-free of the source's parent directory