CVE-2026-9334CWE-843

Cpanel::JSON::XS versions before 4.41 for Perl allow type confusion via duplicate object keys when dupkeys_as_arrayref is enabled

High · published June 3, 2026

CVSS v3.1
7.3
EPSS
0%
Percentile
34.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.3 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS v4.0
Not supplied
EPSS
0.00412 · 34.3th percentile
Weakness
CWE-843 · Access of Resource Using Incompatible Type ('Type Confusion')
Published
2026-06-03T00:15Z
EPSS history
Timeline
  • 03 JUN 00:15Z
    Cpanel::JSON::XS versions before 4.41 for Perl allow type confusion via duplicate object keys when dupkeys_as_arrayref is enabled
    cvelistv5