CLEANSTART-2026-OB56265: WebFlux application running on the Jetty 12 Core reactive adapter serializes response cookies without the sameSite attribute

Q: What deployment conditions make this issue relevant?

It affects Rundeck deployments where a WebFlux application runs on the Jetty 12 Core reactive adapter. In that configuration, response cookies are serialized without the SameSite attribute.

Q: Does exploitation require authentication or user interaction?

The supplied severity vector indicates network-based exploitation with low attack complexity, no privileges required, and no user interaction required. The stated impact is high confidentiality impact, with no integrity or availability impact listed.

Published Nov 11, 2026

Updated

Security vulnerability affects the rundeck package. A WebFlux application running on the Jetty 12 Core reactive adapter serializes response cookies without the sameSite attribute.

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-2026-47889

Frequently Asked Questions

What deployment conditions make this issue relevant?

It affects Rundeck deployments where a WebFlux application runs on the Jetty 12 Core reactive adapter. In that configuration, response cookies are serialized without the SameSite attribute.

Does exploitation require authentication or user interaction?

The supplied severity vector indicates network-based exploitation with low attack complexity, no privileges required, and no user interaction required. The stated impact is high confidentiality impact, with no integrity or availability impact listed.

CLEANSTART-2026-OB56265: WebFlux application running on the Jetty 12 Core reactive adapter serializes response cookies without the sameSite attribute

Affected Software

Remediation

Event History

Child vulnerabilities

Frequently Asked Questions

What deployment conditions make this issue relevant?

Does exploitation require authentication or user interaction?

Company

Resources

Contact

Frequently Asked Questions

What deployment conditions make this issue relevant?

Does exploitation require authentication or user interaction?