CVE-2026-55549
Yamcs: Reflected XSS in the URL of the Authorize Endpoint
MEDIUM 6.5EPSS 1.3%
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.
- Affected
- yamcs
- CVSS v3.1 GITHUB
- 6.5 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - EPSS
- 1.31% chance of exploitation in the next 30 days, 70th percentile
- Nuclei
- medium · CWE-79
- Published
- 2026-08-28
- Updated
- 2026-09-01