CPANSA-Cpanel-JSON-XS-2026-110674: Cpanel-JSON-XS vulnerability

Publisher giterlizzi Document category csaf_security_advisory
Initial release date 2026-10-19T00:00:00 Engine CSAF Perl Toolkit 0.26
Current release date 2026-10-19T00:00:00 Build Date
Current version 1 Status final
CVSS v3.1 Base Score 6.5 Severity Medium
Original language Language en
Also referred to

Vulnerability Description

Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl miss duplicate non-ASCII bare keys, allowing type confusion under dupkeys_as_arrayref in decode_hv.

With allow_barekey, which relaxed enables, a bare key containing a non-ASCII byte is stored as UTF-8 but looked up as raw bytes, so a repeated key escapes the duplicate-key check and replaces the earlier value.

From 4.41, under dupkeys_as_arrayref, a bare repeat replaces the array that collects a key's values with a plain value, and the next quoted repeat pushes onto that value as if it were an array. A JSON integer there is dereferenced as a pointer.

Untrusted JSON decoded with relaxed and dupkeys_as_arrayref can crash the process or dereference an address chosen by a JSON number.

Vulnerabilities

CVE-2026-110674

Vulnerability Description

Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl miss duplicate non-ASCII bare keys, allowing type confusion under dupkeys_as_arrayref in decode_hv.

With allow_barekey, which relaxed enables, a bare key containing a non-ASCII byte is stored as UTF-8 but looked up as raw bytes, so a repeated key escapes the duplicate-key check and replaces the earlier value.

From 4.41, under dupkeys_as_arrayref, a bare repeat replaces the array that collects a key's values with a plain value, and the next quoted repeat pushes onto that value as if it were an array. A JSON integer there is dereferenced as a pointer.

Untrusted JSON decoded with relaxed and dupkeys_as_arrayref can crash the process or dereference an address chosen by a JSON number.

Weakness CWE-176 : Improper Handling of Unicode Encoding

Product status

Known affected
Product Score
Cpanel-JSON-XS greater than or equal 4.33 and less than 4.80
CVSS Version CVSS Vector CVSS Base Score CVSS Base Severity
3.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H 6.5 Medium
Fixed

giterlizzi

Namespace: https://github.com/giterlizzi/

gdt@cpan.org

References

Revision history

Version Date of the revision Summary of the revision
1 Mon Oct 19 00:00:00 2026 First release

Sharing rules

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