Bug 2555757 (CVE-2026-110681)

Summary: CVE-2026-110681 perl-Cpanel-JSON-XS: Use of parent interpreter scalars in cloned threads
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in perl-Cpanel-JSON-XS. A parser object holds its callbacks and its incremental parse buffer as raw scalar pointers. When a new thread is created, these pointers are copied into the new interpreter unchanged. As a result, the child's parser uses, and later frees, scalars that belong to the parent interpreter, which may have already been freed. If a parser is created before a thread starts and is subsequently used inside that thread to process untrusted JSON payloads, it can call freed callbacks and corrupt reference counts. An attacker can exploit this to crash the process, resulting in a Denial of Service (DoS).
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2556467, 2556468    
Bug Blocks:    

Description OSIDB Bzimport 2026-10-19 18:34:06 UTC 
Cpanel::JSON::XS versions before 4.80 for Perl use the parent interpreter's scalars from a parser object cloned into a new ithread.

A parser object holds its callbacks and its incremental parse buffer as raw scalar pointers. When a thread is created, these are copied into the new interpreter unchanged, so the child's parser uses, and later frees, scalars that belong to the parent and may already have been freed there.

A parser created before a thread starts and used inside it can call freed callbacks, corrupt reference counts and crash the process.