Bug 2556461

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Cpanel::JSON::XS versions from 4.42 before 4.80 for Perl let input chunking change the decoded value of top-level numbers in incr_parse.

allow_nonref is enabled by default and incr_parse inherits it. A top-level number, true, false or null has no closing delimiter, so the incremental parser decodes whatever has arrived. The bytes 12 decode as one value when read together, but as 1 and then 2 when split across two reads.

A peer that can influence read boundaries can change how many messages a stream consumer decodes and what values they carry.