CVE-2026-9516

Name	CVE-2026-9516
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1138273

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libcpanel-json-xs-perl (PTS)	bullseye	4.25-1	vulnerable
	bullseye (security)	4.25-1+deb11u1	vulnerable
	bookworm, bookworm (security)	4.35-1+deb12u1	vulnerable
	trixie (security), trixie	4.39-2~deb13u1	vulnerable
	forky, sid	4.42-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libcpanel-json-xs-perl	source	(unstable)	4.41-1			1138273

Notes

[trixie] - libcpanel-json-xs-perl <no-dsa> (Minor issue)
[bookworm] - libcpanel-json-xs-perl <no-dsa> (Minor issue)
[bullseye] - libcpanel-json-xs-perl <postponed> (Minor issue)
https://lists.security.metacpan.org/cve-announce/msg/40653165/
Fixed by: https://github.com/rurban/Cpanel-JSON-XS/commit/dfe1b41a36caba51dc12a2917fe50285d1ffaa7b (4.41)