Cpanel::JSON::XS: Access of Resource Using Incompatible Type
CVE-2026-9334 is a high-severity access of resource using incompatible type vulnerability in Cpanel::JSON::XS from Rurban, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 4.41 as the first without the flaw, so updating Cpanel::JSON::XS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Cpanel::JSON::XS to 4.41 or a later version.
- Update Cpanel to 4.41 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| RURBAN | Cpanel::JSON::XS | before 4.41 | 4.41 |
| Rurban | Cpanel | before 4.41 | 4.41 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by CISA (ADP).
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Access of Resource Using Incompatible Type
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
More Access of Resource Using Incompatible Type vulnerabilities (CWE-843)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/rurban/Cpanel-JSON-XS/commit/11a7c550a0d8fac2f84414f24d5df9b2bfe346e2.patch
- metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.41/changesRelease Notes
- openwall.com/lists/oss-security/2026/06/03/4Mailing List, Third Party Advisory
Other vulnerabilities in Cpanel::JSON::XS
- 7.5 High severity
Recent Access of Resource Using Incompatible Type vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 7.5 High severity
Spotted an error? Tell us.