REDHAT-BUG-2455921: Null Pointer Dereference

A flaw was found in libarchive. A NULL pointer dereference vulnerability exists in the ACL parsing logic, specifically within the archiveaclfromtextnl() function. When processing a malformed ACL string (such as a bare "d" or "default" tag without subsequent fields), the function fails to perform adequate validation before advancing the pointer. An attacker can exploit this by providing a maliciously crafted archive, causing an application utilizing the libarchive API (such as bsdtar) to crash, resulting in a Denial of Service (DoS).