CVE-2026-49421

FreeBSD's unlinkat/funlinkat syscalls validated the AT_RESOLVE_BENEATH flag but silently dropped it during path lookup, allowing processes to delete files outside the intended directory tree. All supported FreeBSD branches are affected; patches were committed on 2026-06-30. No workaround exists; ...

CVE-2026-49421 unlinkat(2) ignores AT_RESOLVE_BENEATH flag

The kernel function that implements unlinkat2 and funlinkat2 validated the ATRESOLVEBENEATH flag but failed to pass it through to the underlying path lookup. The flag was silently dropped, so path resolution was not actually restricted. A process that uses ATRESOLVEBENEATH with unlinkat2 or...

The vulnerability of system calls unlinkat and funlinkat in the kernels of FreeBSD allows a attacker to compromise the integrity of the protected information.

The vulnerability of the unlinkat and funlinkat system calls in FreeBSD operating systems is related to authentication errors. Exploiting this vulnerability can allow an attacker to compromise the integrity of the protected information...

The vulnerability of the unlinkat() function in package managers Nix, Lix, and Guix allows attackers to increase their privileges.

The vulnerability of the unlinkat function in Nix, Lix, and Guix is related to synchronization errors when using a shared resource. Exploiting this vulnerability can allow attackers to increase their privileges...

Configure Audit Rules for File Deletion

Generally, it is highly risky to delete files in the OS. Misoperations by administrators or attacks may cause severe system faults. You are advised to audit and monitor system calls, such as rename, unlink, unlinkat, and renameat, and record deletion operation logs. Deleting system or service fil...