CVE-2026-53576: Kestra: REST API authentication bypass leading to code execution in container
An anonymous caller can bypass the Kestra REST API authentication filter by using a path ending in configs, which allows unauthenticated creation and execution of flows with Shell or Process tasks. The record rates it critical with CVSS 3.1 score 10.0 and states it is fixed in 1.0.45 and 1.3.21. No confirmed active exploitation appears in the sources consulted.
Overview
Kestra is an open-source, event-driven orchestration platform. Versions before 1.0.45 and 1.3.21 contain a flaw in the REST API authentication filter that lets certain requests skip the credential check. The weakness is classified as code injection (CWE-94) in the record.
Impact
The record rates this as critical, with CVSS 3.1 base score 10.0 and vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. According to the record, an unauthenticated caller can create a flow with a Shell or Process task and run it, and the task runs as root inside the Kestra container. Because the official docker-compose.yml mounts the Docker socket, the record notes that root in the container can reach the host Docker daemon.
Affected products and versions
- Product: Kestra (vendor listed as Kestra Kestra).
- Affected ranges in the record: versions below 1.0.45, and versions from 1.1.0 up to but not including 1.3.21.
- Fixed versions stated in the record: 1.0.45 and 1.3.21.
- The record does not describe other deployment variants or additional fixed branches.
Exploitation status
The KEV data in the record shows this CVE is not listed in the CISA Known Exploited Vulnerabilities catalog. No confirmed active exploitation appears in the sources consulted. One reference is tagged 'Exploit' in the record, but that tag alone does not establish that attacks have occurred.
Remediation and mitigation
- Upgrade Kestra to 1.0.45 or 1.3.21, whichever matches your deployment line, as stated in the advisory.
- The only fixed version listed for the 1.1.0 to 1.3.21 range is 1.3.21, so treat that as the target for deployments in that range.
- Until the upgrade is applied, restrict network access to the Kestra API to trusted networks and only through controlled reverse proxies.
- Review whether the Docker socket mount in the deployment is necessary. Removing unneeded host-level access reduces the impact of a container compromise.
Detection guidance
- Review API and reverse proxy logs for unauthenticated requests to flow creation and execution endpoints.
- Look for newly created flows that include Shell or Process tasks, especially those tied to anonymous or unknown identities.
- Monitor the Kestra container for unexpected processes and for Docker API activity originating from it.
Limitations of the available information
The record does not include full vendor technical details, a list of all affected deployments, or fix details for every branch within the affected range. Whether this vulnerability has been exploited in the wild is unknown from the available data. Exposure in a given environment depends on network reachability and on whether the Docker socket is mounted.
Frequently asked questions
What is the core problem in CVE-2026-53576?
The REST API authentication filter in Kestra treats certain paths as public, so some requests reach protected routes without a credential check. The record links this to code injection (CWE-94).
Which versions are fixed?
The record states that the vulnerability is fixed in versions 1.0.45 and 1.3.21. The affected ranges are below 1.0.45 and from 1.1.0 up to but not including 1.3.21.
Is this vulnerability known to be actively exploited?
The record shows it is not listed in the CISA KEV catalog, and no confirmed active exploitation appears in the sources consulted.
This analysis was drafted with AI assistance from verified source data and automatically checked against it.