CVE-2026-110682: 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

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-19 · updated 2026-10-29
Weakness: CWE-436

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

Cpanel-JSON-XS: from 4.42 before 4.80 — fixed in 4.80

How to fix

Upgrade to a fixed version: Cpanel-JSON-XS 4.80. Check the vendor advisory for mitigations.

References

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