SEPTEMBER 17, 2026
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Case File

CVE-2026-55549

MEDIUM · CVSS 6.5 EPSS 0.36% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-28 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

Yamcs versions prior to 5.9.4 are vulnerable to a reflected cross-site scripting (XSS) attack due to inadequate HTML escaping of the attacker-controlled redirect_uri parameter in the authorization process. An attacker can exploit this vulnerability to execute malicious JavaScript in the context of a Yamcs user’s browser, potentially compromising authentication credentials. Organizations using Yamcs for mission control should prioritize upgrading to version 5.9.4 to mitigate this risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-55549
Severity
MEDIUM
CVSS
6.5
EPSS
0.36%
Java

Original NVD 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.