Yamcs is a mission control framework. Prior to 5.9.4, Yamcs reflects an attacker-controlled redirect_uri parameter from GET /auth/authorize into yamcs-core/src/main/resources/auth/templates/authorize.html without adequate HTML escaping by yamcs-core/src/main/java/org/yamcs/http/auth/AuthHandler.java and yamcs-core/src/main/java/org/yamcs/http/HandlerContext.java. A crafted authorization URL can execute JavaScript when opened by a Yamcs user. The script can access browser-held authentication material and transmit it to an attacker, enabling account compromise. This issue is fixed in version 5.9.4.
History

Fri, 28 Aug 2026 22:00:00 +0000

Type Values Removed Values Added
First Time appeared Yamcs
Yamcs yamcs
Vendors & Products Yamcs
Yamcs yamcs

Fri, 28 Aug 2026 19:45:00 +0000

Type Values Removed Values Added
Description Yamcs is a mission control framework. Prior to 5.9.4, Yamcs reflects an attacker-controlled redirect_uri parameter from GET /auth/authorize into yamcs-core/src/main/resources/auth/templates/authorize.html without adequate HTML escaping by yamcs-core/src/main/java/org/yamcs/http/auth/AuthHandler.java and yamcs-core/src/main/java/org/yamcs/http/HandlerContext.java. A crafted authorization URL can execute JavaScript when opened by a Yamcs user. The script can access browser-held authentication material and transmit it to an attacker, enabling account compromise. This issue is fixed in version 5.9.4.
Title Yamcs: Reflected XSS in the URL of the Authorize Endpoint
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-28T17:15:52.840Z

Reserved: 2026-06-16T23:01:04.075Z

Link: CVE-2026-55549

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-28T20:18:28.657

Modified: 2026-08-28T20:18:28.657

Link: CVE-2026-55549

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-28T21:45:03Z