CVE-2026-2736 PUBLISHED

Reflected Cross-Site Scripting (XSS) vulnerability in Alkacon's OpenCms

Assigner: INCIBE
Reserved: 19.02.2026 Published: 19.02.2026 Updated: 19.02.2026

Reflected Cross-site Scripting (XSS) in Alkacon's OpenCms v18.0, which allows an attacker to execute JavaScript code in the victim's browser by sending the victim a malicious URL containing the ‘q’ parameter in ‘/search/index.html’. This vulnerability can be exploited to steal sensitive user information such as session cookies, or to perform actions while impersonating the user.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CVSS Score: 5.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	Low
Attack Complexity	Low	Integrity	None	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	Active

CVSS 4.0

Product Status

Vendor	Alkacon
Product	OpenCms
Versions	Default: unaffected Version 18.0 is affected

Solutions

The vulnerabilities have been fixed by the Alkacon team in version 19.0.

Credits

Gonzalo Aguilar García (6h4ack) finder

References

https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-alkacons-opencms

Problem Types

CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') CWE