CVE-2026-9516: CWE-763 Release of Invalid Pointer or Reference in RURBAN Cpanel::JSON::XS
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.
AI Analysis
Technical Summary
CVE-2026-9516 affects Cpanel::JSON::XS versions prior to 4.41. The vulnerability arises because decode_json() advances the input scalar's string pointer to skip a UTF-8 BOM but only restores it on normal return. If a decode filter callback throws an exception, the pointer is not restored, leaving the scalar with an invalid pointer offset. When the scalar is later freed, this results in the allocator receiving an invalid pointer, causing the Perl interpreter to abort. This can be triggered by decoding a single BOM-prefixed JSON document with a throwing filter callback, resulting in a denial of service.
Potential Impact
The vulnerability allows an attacker to cause a denial of service by crashing the Perl interpreter when processing specially crafted JSON input with a UTF-8 BOM prefix and a throwing decode filter callback. There is no impact on confidentiality or integrity, but availability is affected due to the interpreter crash.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid processing UTF-8 BOM prefixed JSON input with decode filter callbacks that may throw exceptions. Monitor vendor channels for updates and apply official patches once released.
CVE-2026-9516: CWE-763 Release of Invalid Pointer or Reference in RURBAN Cpanel::JSON::XS
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 v3.1
Score 7.5high
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-9516 affects Cpanel::JSON::XS versions prior to 4.41. The vulnerability arises because decode_json() advances the input scalar's string pointer to skip a UTF-8 BOM but only restores it on normal return. If a decode filter callback throws an exception, the pointer is not restored, leaving the scalar with an invalid pointer offset. When the scalar is later freed, this results in the allocator receiving an invalid pointer, causing the Perl interpreter to abort. This can be triggered by decoding a single BOM-prefixed JSON document with a throwing filter callback, resulting in a denial of service.
Potential Impact
The vulnerability allows an attacker to cause a denial of service by crashing the Perl interpreter when processing specially crafted JSON input with a UTF-8 BOM prefix and a throwing decode filter callback. There is no impact on confidentiality or integrity, but availability is affected due to the interpreter crash.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid processing UTF-8 BOM prefixed JSON input with decode filter callbacks that may throw exceptions. Monitor vendor channels for updates and apply official patches once released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CPANSec
- Date Reserved
- 2026-05-25T18:54:26.396Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1f765ee29bf47b50276b28
Added to database: 06/03/2026, 00:33:34 UTC
Last enriched: 06/10/2026, 11:06:04 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 97
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.