CVE-2026-53576
Kestra: Unauthenticated RCE via /configs path-suffix auth-filter bypass
- Published
- Jun 26, 2026
- Updated
- Jun 29, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HLow · next 30 days
- Percentile
- 88.3%
- Model date
- Oct 15, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, the authentication filter for the REST API (@Filter("/api/v1/**")) treats any request whose path ends in /configs as the public instance-config endpoint and forwards it without a credential check. kestra addresses its resources by URL path segments that the caller chooses (/api/v1/{tenant}/flows/{namespace}, /api/v1/{tenant}/executions/{namespace}/{id}, /api/v1/{tenant}/namespaces/{namespace}/kv/{key}). An anonymous caller picks the literal configs as the final segment, and the request bypasses Basic-Auth entirely. Because the bypass reaches the flow-create and execution-trigger routes, an unauthenticated caller creates a flow containing a Shell or Process task and runs it. The task executes as root inside the kestra container. The official docker-compose.yml mounts /var/run/docker.sock, so root in the container reaches the host Docker daemon. This vulnerability is fixed in 1.0.45 and 1.3.21.
Sources
http/cves/2026/CVE-2026-53576.yaml
Nuclei TemplatesDeclared conditions
- network: http($.protocol_keys)
- verification: dsl($.matchers[*].type)
- oob: interactsh_reference($.template_text)
Responsible use
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