Vulnerability · Published Jun 3, 2026 · Assigned by CPANSec
CVE-2026-9334Cpanel::JSON::XS versions before 4.41 for Perl allow type confusion via duplicate object keys when dupkeys_as_arrayref is enabled
High 7.3
In plain English
A high-severity type confusion in Cpanel::JSON::XS from RURBAN. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libcpanel-json-xs-perl | no fix listed | DEBIAN-CVE-2026-9334 |
| Debian:13 | libcpanel-json-xs-perl | no fix listed | DEBIAN-CVE-2026-9334 |
| Debian:14 | libcpanel-json-xs-perl | 4.41-1 | DEBIAN-CVE-2026-9334 |
| Ubuntu:22.04:LTS | libcpanel-json-xs-perl | no fix listed | UBUNTU-CVE-2026-9334 |
| Ubuntu:24.04:LTS | libcpanel-json-xs-perl | no fix listed | UBUNTU-CVE-2026-9334 |
| Ubuntu:25.10 | libcpanel-json-xs-perl | no fix listed | UBUNTU-CVE-2026-9334 |
| Ubuntu:26.04:LTS | libcpanel-json-xs-perl | no fix listed | UBUNTU-CVE-2026-9334 |
| Ubuntu:26.10 | libcpanel-json-xs-perl | no fix listed | UBUNTU-CVE-2026-9334 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| RURBAN | Cpanel::JSON::XS | 0 – before 4.41 |
Weakness: CWE-843 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L