CVE-2026-9334

Name	CVE-2026-9334
Description	Cpanel::JSON::XS versions before 4.41 for Perl allow type confusion via duplicate object keys when dupkeys_as_arrayref is enabled. decode_hv() collapses duplicate object keys into an array reference under dupkeys_as_arrayref. The branch reached for a duplicate key tests `SvTYPE (old_value) != SVt_RV && SvTYPE (SvRV (old_value)) != SVt_PVAV`, which evaluates SvRV(old_value) before establishing that old_value is a reference. When the existing value is a plain scalar rather than an array reference, a non-reference scalar is dereferenced as a reference. A caller decoding untrusted JSON with dupkeys_as_arrayref enabled is crashed, and the incompatible access follows a pointer taken from attacker controlled scalar contents.
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/40653179/
Fixed by: https://github.com/rurban/Cpanel-JSON-XS/commit/11a7c550a0d8fac2f84414f24d5df9b2bfe346e2 (4.41)