Insecure Deserialisation via Plaintext HTTP leading to Remote Code Execution in Quick.CMS

published 2026-06-15 4 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-36703

cvss: 7.5; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits: 0; none known

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.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 4 mo ago (2026-06-15)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	7.5	CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
CNA	4.0	7.5	CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/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

Affected products

OpenSolution Quick.CMS

Classification

Weakness

CWE-502 Deserialization of Untrusted Data
CWE-94 Improper Control of Generation of Code

References

cert.pl /posts/2026/06/CVE-2026-11860/
third-party-advisory
opensolution.org /
product

Sources

CVE List CVE-2026-11860
NVD CVE-2026-11860

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Summary