Deserialization in B2evolution Cms
CVE-2026-76834
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.
Vulnerability class: Insecure Deserialization
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (technical-description, patch)
- disclosure@vulncheck.com (vendor-advisory)
- disclosure@vulncheck.com (product)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-76834?
- CVE-2026-76834 is a high-severity vulnerability in B2evolution Cms, classified under Deserialization of Untrusted Data. CVSS score: 8.1/10. Published 2026-09-17.
- How severe is CVE-2026-76834?
- High severity. CVSS v3 base score is 8.1 out of 10.