Sereal::Decoder versions from 4.000 through 4.009_002 for Perl is vulnerable to a buffer overwrite flaw in the Zstandard library.
Sereal::Decoder embeds a version of the Zstandard (zstd) library that is vulnerable to CVE-2019-11922. This is a race condition in the one-pass compression functions of Zstandard prior to version 1.3.8 could allow an attacker to write bytes out of bounds if an output buffer smaller than the recommended size was used.
Upgrade to Sereal::Decoder version 4.010 or later.