cPanel CVE-2026-110684
CVE-2026-110684 is one of a coordinated set of fixes in Cpanel::JSON::XS for Perl: versions before 4.80 — leak memory and retain overloaded objects when encoding values as strings in encode_stringify. The corrected build is Cpanel::JSON::XS 4.80, delivered to cPanel & WHM servers through the standard update channel.
What this means under a SharedLicense license
Parsing untrusted JSON with the affected Cpanel::JSON::XS builds is the exposure: CWE-401 in the advisory's own data, CVSS 8.1 — practical risk ranges from resource exhaustion to memory corruption.
Cpanel::JSON::XS versions from 3.0202 before 4.80 for Perl leak memory and retain overloaded objects when encoding values as strings in encode_stringify.
encode_stringify writes a value in its string form under allow_stringify, under convert_blessed for objects without TO_JSON, and under allow_bignum. For an array or hash object with a «» overload, and from 4.20 a scalar object, it takes an extra reference that is never released, so the object and everything it references are never freed. From 4.10 it also never frees its copy of the string.
Repeatedly encoding data that contains such values grows process memory without bound.
Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-110684
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