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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.008 (58.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
Weakness classification (CWE)
References
- gist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64e (technical-description)
- github.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.funcs.php (technical-description)
- github.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin.php (technical-description)
- github.com/b2evolution/b2evolution/commit/25c21cf9cc4261324001f9039509710b37ee2… (patch)
- github.com/b2evolution/b2evolution/commit/999b5ad1d59760d7e450ceb541f55432fc74c… (patch)
- github.com/b2evolution/b2evolution/commit/335abf09bcea61717bd00bc1e3889f8100ebd… (technical-description, patch)
- b2evolution.net/news/2022/03/26/2022-update-eol (vendor-advisory)
- github.com/b2evolution/b2evolution (product)
- www.vulncheck.com/advisories/b2evolution-cms-6.7.8-through-7.2.5-object-injecti… (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.