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.
References9
- b2evolution.net/news/2022/03/26/2022-update-eol
- gist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64e
- github.com/b2evolution/b2evolution
- github.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin…
- github.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.…
- github.com/b2evolution/b2evolution/commit/25c21cf9cc4261324001f…
- github.com/b2evolution/b2evolution/commit/335abf09bcea61717bd00…
- github.com/b2evolution/b2evolution/commit/999b5ad1d59760d7e450c…
- www.vulncheck.com/advisories/b2evolution-cms-6.7.8-through-7.2.…
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 4.0
-
9.2
CRITICAL
Score source: CNA
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 1% percentile: 58 · as of 8 November 2026
- CWE
- CWE-502
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.