CVE-2026-76834
Medium
Elevated severity or exploit probability.
CVSS base
8.1
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
1.2%
67.5th percentile
CISA KEV
Not listed
Weakness / dates
CWE-502
Published 2026-09-17 · modified 2026-09-23
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.
References
- https://b2evolution.net/news/2022/03/26/2022-update-eol
- https://gist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64e
- https://github.com/b2evolution/b2evolution
- https://github.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin.php#L49
- https://github.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.funcs.php#L2860
- https://github.com/b2evolution/b2evolution/commit/25c21cf9cc4261324001f9039509710b37ee2c4d
- https://github.com/b2evolution/b2evolution/commit/335abf09bcea61717bd00bc1e3889f8100ebd1bb
- https://github.com/b2evolution/b2evolution/commit/999b5ad1d59760d7e450ceb541f55432fc74cd27
- https://www.vulncheck.com/advisories/b2evolution-cms-6.7.8-through-7.2.5-object-injection-via-negative-integer-array-key