CLEANSTART-2026-TU12013: Spring MVC and WebFlux applications are vulnerable to stream corruption when using Server-Sent Events (SSE) with view fragments

Q: What conditions make a deployment exposed?

The affected deployment must use the rundeck package and run a Spring MVC or WebFlux application that uses Server-Sent Events with view fragments.

Q: Does exploitation require authentication or user interaction?

The supplied CVSS vector indicates network access, low attack complexity, no privileges required, and no user interaction required.

Q: What is the potential impact if exploited?

The vulnerability is rated critical at 9.8, with high potential impact to confidentiality, integrity, and availability. The CVSS vector indicates scope is unchanged.

Published Nov 11, 2026

Updated

Security vulnerability affects the rundeck package. Spring MVC and WebFlux applications are vulnerable to stream corruption when using Server-Sent Events (SSE) with view fragments.

Affected Software

2 affected componentsFixes available

cleanstart/rundeck<6.3.0-r0

6.3.0-r0

cleanstart/rundeck<6.1.0-r4

6.1.0-r4

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade cleanstart/rundeck to a version that resolves this vulnerability.
Fixed in 6.3.0-r0
Upgrade
Upgrade cleanstart/rundeck to a version that resolves this vulnerability.
Fixed in 6.1.0-r4

Event History

Nov 11, 2026

Advisory Published

via OSV·12:39 AM

Data Sourced

via OSV·12:39 AM

DescriptionSeverityAffected Software

Child vulnerabilities

Contains the following vulnerabilities.

CVE-2026-47890

Frequently Asked Questions

What conditions make a deployment exposed?

The affected deployment must use the rundeck package and run a Spring MVC or WebFlux application that uses Server-Sent Events with view fragments.

Does exploitation require authentication or user interaction?

The supplied CVSS vector indicates network access, low attack complexity, no privileges required, and no user interaction required.

What is the potential impact if exploited?

The vulnerability is rated critical at 9.8, with high potential impact to confidentiality, integrity, and availability. The CVSS vector indicates scope is unchanged.

CLEANSTART-2026-TU12013: Spring MVC and WebFlux applications are vulnerable to stream corruption when using Server-Sent Events (SSE) with view fragments

Affected Software

Remediation

Event History

Child vulnerabilities

Frequently Asked Questions

What conditions make a deployment exposed?

Does exploitation require authentication or user interaction?

What is the potential impact if exploited?

Company

Resources

Contact

Frequently Asked Questions

What conditions make a deployment exposed?

Does exploitation require authentication or user interaction?

What is the potential impact if exploited?