CVE-2026-9334 PUBLISHED

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

Assigner: CPANSec
Reserved: 22.05.2026 Published: 03.06.2026 Updated: 03.06.2026

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.

Product Status

Vendor RURBAN
Product Cpanel::JSON::XS
Versions Default: unaffected
  • affected from 0 to 4.41 (excl.)

Solutions

Upgrade to Cpanel::JSON::XS 4.41 or later.

References

Problem Types

  • CWE-843 Access of Resource Using Incompatible Type ('Type Confusion') CWE