Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Cpanel-JSON-XS | 4.42 – < 4.80 | 4.80 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libcpanel-json-xs-perl | 4.80-1 | — |
| Debian 13 | libcpanel-json-xs-perl | No fix yet | — |
| Debian 12 | libcpanel-json-xs-perl | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 26.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 24.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 22.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 20.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
| Ubuntu 16.04 LTS | libcpanel-json-xs-perl | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | perl-Cpanel-JSON-XS | 4.800.0-150700.3.9.1 | SUSE-SU-2026:4926-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | perl-Cpanel-JSON-XS | 4.800.0-1.1 | openSUSE-SU-2026:12217-1 |
| openSUSE Leap 16.0 | perl-Cpanel-JSON-XS | 4.800.0-bp160.1.1 | openSUSE-SU-2026:22187-1 |
Advisories 3
- openSUSE-SU-2026:22187-1 Security update for perl-Cpanel-JSON-XS SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:4926-1 Security update for perl-Cpanel-JSON-XS SUSE / openSUSE Security Updates · Oct 29, 2026
- openSUSE-SU-2026:12217-1 perl-Cpanel-JSON-XS-4.800.0-1.1 on GA media SUSE / openSUSE Security Updates · Oct 22, 2026