Kestra unauthenticated RCE exploited in wild (CVE-2026-49869)

Actively exploited in the wild - CVE-2026-49869 is a critical authentication bypass in Kestra OSS before 1.0.45 and 1.3.21 that grants unauthenticated remote code execution as root inside the worker container. Patched in 1.0.45 and 1.3.21 - update immediately.

Overview

Kestra, the open-source event-driven orchestration platform, suffers from a severe authentication flaw in its AuthenticationFilter. The filter uses request.getPath().endsWith("/configs") to whitelist the public configuration endpoint from Basic Auth. Because this is a suffix match rather than an exact path match, any API endpoint whose final path segment is configs bypasses authentication entirely.

An unauthenticated remote attacker can exploit this flaw to reach internal APIs that should require credentials. By crafting requests to paths ending in /configs, the attacker gains full access to Kestra’s orchestration features, including the ability to create and execute arbitrary workflows without any authentication.

The impact is amplified because Kestra ships with script execution plugins (plugin-script-shell, plugin-script-python, and similar) enabled by default. This means the attacker can immediately leverage workflow creation to execute arbitrary operating system commands, achieving full remote code execution as root inside the Kestra worker container.

Affected Systems

• Kestra OSS versions prior to 1.0.45
• Kestra OSS versions prior to 1.3.21

The vulnerability carries a CVSS score of 10.0 (Critical), reflecting the combination of network accessibility, zero privileges required, and remote code execution impact. CISA has added this CVE to its Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The EPSS model estimates just a 1.0% probability of exploitation in the next 30 days, but this low probability should not diminish the urgency given confirmed in-the-wild attacks.

Remediation

Organizations running Kestra OSS should upgrade immediately:

• Version 1.0.x users: Upgrade to 1.0.45 or later
• Version 1.3.x users: Upgrade to 1.3.21 or later

If immediate patching is not possible, restrict network access to Kestra API endpoints as a temporary mitigation. Place Kestra behind a reverse proxy that enforces authentication before requests reach the application, and monitor logs for suspicious requests to paths ending in /configs.

For threat intelligence on related orchestration platform attacks, review our breach reports and follow the latest developments in our security news section.

Security Insight

This vulnerability highlights a recurring class of flaws: suffix-based path matching for security-critical decisions. Similar issues have plagued other platforms where developers use endsWith() or contains() instead of exact path matching for authentication whitelists. The decision to enable dangerous plugins by default compounds the risk - a design choice that converts an authentication bypass into trivial remote code execution. Vendors of orchestration platforms should treat plugin defaults as security boundaries and audit all authentication checks for path comparison correctness.

Further Reading

• All Critical Vulnerabilities
• Recent Critical Vulnerabilities
• Top Critical CVEs