CVE-2026-76834 b2evolution CMS 6.7.8 through 7.2.5 Object Injection via Negative Integer Array Key
Unauthenticated attackers can achieve code execution in b2evolution CMS by bypassing validation checks to inject malicious serialized PHP objects.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-76834?
CVE-2026-76834 is a critical unsafe deserialization vulnerability in b2evolution CMS, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-502
Which versions are affected by CVE-2026-76834?
How do I fix CVE-2026-76834?
No fix has been published for CVE-2026-76834 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-76834 being exploited?
There is no known exploitation of CVE-2026-76834 in the wild and no public exploit code.
Sources
Also known as GHSA-2vrr-cgr4-gfmm.