archive_read_format_rar_read_data in archive_read_support_format_rar.c in libarchive before 3.4.0 has a use-after-free in a certain ARCHIVE_FAILED situation, related to Ppmd7_DecodeSymbol.
"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18408.json"