CVE-2026-9334: Rurban Cpanel::json::xs

High severity, CVSS 7.3. EPSS: 0.4% chance of exploitation in the next 30 days.

Cpanel::JSON::XS versions before 4.41 for Perl allow type confusion via duplicate object keys when dupkeys_as_arrayref is enabled. decode_hv() collapses duplicate object keys into an array reference under dupkeys_as_arrayref. The branch reached for a duplicate key tests `SvTYPE (old_value) != SVt_RV && SvTYPE (SvRV (old_value)) != SVt_PVAV`, which evaluates SvRV(old_value) before establishing that old_value is a reference. When the existing value is a plain scalar rather than an array reference, a non-reference scalar is dereferenced as a reference. A caller decoding untrusted JSON with dupkeys_as_arrayref enabled is crashed, and the incompatible access follows a pointer taken from attacker controlled scalar contents.

Affected products

• Rurban Cpanel::json::xs: before 4.41 (fixed in 4.41)

Published 2026-06-03. Last modified 2026-07-21.