Bug 2555767 (CVE-2026-110686)

Summary: CVE-2026-110686 perl-Cpanel-JSON-XS: Use-after-free in decode_hv filter callbacks
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in perl-Cpanel-JSON-XS. During decoding, the parser copies the filter_json_object and filter_json_single_key_object callbacks without taking references to them. If a filter callback removes the last single-key filter, it frees the callback table while the ongoing decode process is still using it. This use-after-free condition causes the next object to be dispatched through the freed memory, allowing an attacker providing a maliciously crafted JSON payload to crash the process, resulting in a Denial of Service (DoS).
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Bug Depends On: 2556480, 2556481    
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Description OSIDB Bzimport 2026-10-19 18:38:44 UTC 
Cpanel::JSON::XS versions before 4.80 for Perl use freed filter callbacks when a filter removes itself during decoding in decode_hv.

A decode copies the parser's filter_json_object and filter_json_single_key_object callbacks without taking references to them. A filter callback that removes the last single-key filter frees the callback table while the decode in progress still uses it. The next object is dispatched through freed memory and can crash the process.