CVE-2026-9334 Memory corruption in Cpanel::JSON::XS
Attackers can cause crashes or potential code execution in Perl applications using Cpanel::JSON::XS with duplicate key handling enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-9334?
CVE-2026-9334 is a high-severity memory corruption vulnerability in RURBAN Cpanel::JSON::XS, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-843
Which versions are affected by CVE-2026-9334?
It affects 1 product.
Products include Rurban Cpanel\.
How do I fix CVE-2026-9334?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-9334 being exploited?
There is no known exploitation of CVE-2026-9334 in the wild and no public exploit code.
Other vulnerabilities in RURBAN Cpanel::JSON::XS
Sources
Also known as AZL-89396, DEBIAN-CVE-2026-9334, GHSA-qfqj-xxqv-cxfw, UBUNTU-CVE-2026-9334.