CVE-2026-9516 | THREATINT

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.

PUBLISHED Reserved 2026-05-25 | Published 2026-06-03 | Updated 2026-06-03 | Assigner CPANSec

Problem types

CWE-763 Release of Invalid Pointer or Reference

CWE-755 Improper Handling of Exceptional Conditions

Product status

Default status
unaffected

Any version before 4.41
affected

Timeline

References

github.com/…dfe1b41a36caba51dc12a2917fe50285d1ffaa7b.patch patch

metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.41/changes release-notes

cve.org (CVE-2026-9516)

nvd.nist.gov (CVE-2026-9516)

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