by Kastro
Paper/Archive/CVE-2026-76834

CVE-2026-76834

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

EPSS 0.8%CVSS 9.2
critical.is priorityof 100
39
CVSS 9.2 (CNA)9.2 / 10 × 3027.6Not in CISA KEV+300.0EPSS percentile 58.1.581 × 2011.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
b2evolution CMS6.7.8 – 7.2.5–CNA

Scores by source

VulnCheck (CNA)9.2CVSS: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 (CNA)8.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

writeupgist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64ewriteupgithub.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.funcs.php#L2860writeupgithub.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin.php#L49patchgithub.com/b2evolution/b2evolution/commit/25c21cf9cc4261324001f9039509710b37ee2c4dpatchgithub.com/b2evolution/b2evolution/commit/999b5ad1d59760d7e450ceb541f55432fc74cd27patchgithub.com/b2evolution/b2evolution/commit/335abf09bcea61717bd00bc1e3889f8100ebd1bbadvisoryb2evolution.net/news/2022/03/26/2022-update-eolrefgithub.com/b2evolution/b2evolutionwriteupvulncheck.com/advisories/b2evolution-cms-6.7.8-through-7.2.5-object-injection-via-negative-integer-array-key