CVE-2026-76834

b2evolution CMS 6.7.8 through 7.2.5 Object Injection via Negative Integer Array Key

State: Published
Severity: 9.2 Critical
Published: Sep 17, 2026
Updated: Sep 18, 2026
Reserved: Aug 19, 2026

Description

b2evolution CMS versions 6.7.8 through 7.2.5 contain an incomplete fix for CVE-2016-8901 where the serialized-array object check in param_check_serialized_array() fails to reject payloads with negative integer array keys. Unauthenticated attackers can submit crafted serialized PHP objects via POST requests to htsrv/call_plugin.php that bypass validation and reach unserialize(), instantiating arbitrary PHP objects with attacker-chosen properties that may enable code execution if suitable POP gadget chains exist.

Scores

CVSS	Score	Vector	Source
4.0	9.2 Critical	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	VulnCheck
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	VulnCheck

Weaknesses

CWE-502 Deserialization of Untrusted Data

Affected Products

Product	Versions
b2evolution CMSb2evolution	6.7.8 through 7.2.5Affected

References

https://gist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64etechnical-description
https://github.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.funcs.php#L2860technical-description
https://github.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin.php#L49technical-description
Incomplete fix for CVE-2016-8901 (1 of 2)patch
Incomplete fix for CVE-2016-8901 (2 of 2)patch
Introduces the flawed regular expression, first released in 6.7.8technical-descriptionpatch
b2evolution CMS end-of-life announcementvendor-advisory
https://github.com/b2evolution/b2evolutionproduct
VulnCheck Advisory: b2evolution CMS 6.7.8 through 7.2.5 Object Injection via Negative Integer Array Keythird-party-advisory

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