CVE-2026-76834

9.2 CRITICAL 0.8% exploit odds Fix listed Code execution Web app

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-08-19 20:34 UTC ReservedThe CVE id was reserved by its CNA
2026-09-17 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-23 17:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.8% in the next 30 days (EPSS).
Severity: 9.2 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-09-17 16:17 UTC
Last modified: 2026-09-23 17:17 UTC
Exploit probability: 0.8% · EPSS, next 30 days
Weakness: CWE-502 · Unsafe deserialization
Record status: Deferred

Attack profile CVSS 4.0 · 9.2

Attack vector: Network
Complexity: Low
Attack requirements: Present
Privileges needed: None
User interaction: None
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-76834.md and follow it. Check whether this project is affected by CVE-2026-76834. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record