IM
IronMonkey Threat Research

CVE-2026-9516 HIGH

Published: 2026-06-03 | Last Modified: 2026-06-03 | Status: Received

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.

CVSS Metrics

Base Score: 7.5 (HIGH)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack VectorNETWORK
Attack ComplexityLOW
Privileges RequiredNONE
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactNONE
Integrity ImpactNONE
Availability ImpactHIGH

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Type: Secondary

Exploitability Score: 3.9

Impact Score: 3.6

Weaknesses

Source Type Description
9b29abf9-4ab0-4765-b253-1875cd9b441e Secondary
en CWE-755
en CWE-763
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