Cpanel::JSON::XS versions before 4.41 for Perl allow denial of service via UTF-8 BOM prefixed input when a decode filter callback throws.

To skip a leading 3-byte UTF-8 BOM, decode_json() advances the input scalar's string pointer past the mark with SvPV_set() and restores it only on the normal return path. When decoding aborts through a Perl exception, for example a filter_json_object callback that croaks, the restore is skipped and the scalar is left with its string pointer offset into its own buffer and a shortened length.

When that scalar is later freed, the allocator receives an invalid pointer and the interpreter aborts. A single BOM prefixed document decoded with a throwing filter callback crashes any caller.

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Fixes

Solution

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


Workaround

No workaround given by the vendor.

History

Wed, 03 Jun 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 03 Jun 2026 11:15:00 +0000

Type Values Removed Values Added
References

Wed, 03 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
First Time appeared Rurban
Rurban cpanel::json::xs
Vendors & Products Rurban
Rurban cpanel::json::xs

Wed, 03 Jun 2026 02:30:00 +0000

Type Values Removed Values Added
Description Cpanel::JSON::XS versions before 4.41 for Perl allow denial of service via UTF-8 BOM prefixed input when a decode filter callback throws. To skip a leading 3-byte UTF-8 BOM, decode_json() advances the input scalar's string pointer past the mark with SvPV_set() and restores it only on the normal return path. When decoding aborts through a Perl exception, for example a filter_json_object callback that croaks, the restore is skipped and the scalar is left with its string pointer offset into its own buffer and a shortened length. When that scalar is later freed, the allocator receives an invalid pointer and the interpreter aborts. A single BOM prefixed document decoded with a throwing filter callback crashes any caller.
Title Cpanel::JSON::XS versions before 4.41 for Perl allow denial of service via UTF-8 BOM prefixed input when a decode filter callback throws
Weaknesses CWE-755
CWE-763
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-06-03T15:58:49.426Z

Reserved: 2026-05-25T18:54:26.396Z

Link: CVE-2026-9516

cve-icon Vulnrichment

Updated: 2026-06-03T09:35:39.521Z

cve-icon NVD

Status : Received

Published: 2026-06-03T01:16:23.430

Modified: 2026-06-03T18:16:30.357

Link: CVE-2026-9516

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-03T19:30:36Z

Weaknesses