High severity · published Jun 3, 2026
CVE-2026-9334
Cpanel::JSON::XS versions before 4.41 for Perl allow type confusion via duplicate object keys when dupkeys_as_arrayref is enabled
7.3
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 17% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CP
Cpanel::JSON::XS · RURBAN
before 4.41 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-9334
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-9334
Patch
https://github.com/rurban/Cpanel-JSON-XS/commit/11a7c550a0d8fac2f84414f24d5df9b2bfe346e2.patch
Release Notes
https://metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.41/changes
Mailing List
http://www.openwall.com/lists/oss-security/2026/06/03/4
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