CVE-2026-11860 Insecure Deserialisation via Plaintext HTTP leading to Remote Code Execution in Quick.CMS
Attackers can execute arbitrary code on Quick.CMS servers by injecting malicious serialized payloads over plaintext HTTP, requiring admin interaction.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-11860?
CVE-2026-11860 is a high-severity unsafe deserialization vulnerability in OpenSolution Quick.CMS, published on 15 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Quick.CMS deserializes user-controlled data received over plaintext HTTP without ensuring integrity or authenticity. This allows attackers to tamper with serialized payloads in transit and inject malicious objects. Because deserialization is performed without proper validation or class restrictions, crafted payloads can trigger dangerous magic methods (e.g., __wakeup() and __destruct()) and leverage gadget chains, resulting in arbitrary code execution. Exploitation is triggered automatically when an administrator accesses the admin panel.
When successfully exploited, this vulnerability allows attackers to execute arbitrary code on the server via manipulated serialized data transmitted over an unprotected channel.
This issue was mitigated by limiting the communication to HTTPS in a patch for version 6.8 published on 14.05.2026, deployments without this patch remain vulnerable.
Which versions are affected by CVE-2026-11860?
How do I fix CVE-2026-11860?
No fix has been published for CVE-2026-11860 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-2026-11860 being exploited?
There is no known exploitation of CVE-2026-11860 in the wild and no public exploit code.
Sources
Also known as GHSA-vwj5-2gmw-wjp6.