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.

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.

perl-Cpanel-JSON-XS-4.800.0-1.1 on GA media

Affected: Ubuntu:16.04:LTS: libcpanel-json-xs-perl, Ubuntu:18.04:LTS: libcpanel-json-xs-perl, Ubuntu:20.04:LTS: libcpanel-json-xs-perl, Ubuntu:22.04:LTS: libcpanel-json-xs-perl, Ubuntu:24.04:LTS: libcpanel-json-xs-perl, Ubuntu:26.10: libcpanel-json-xs-perl, Ubuntu:26.04:LTS: libcpanel-json-xs-perl

(Cpanel::JSON::XS versions from 4.42 before 4.80 for Perl let input chu ...)