Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

Kestra OSS OS Command Injection Vulnerability

Added to KEV
2026-09-02
Federal due date
2026-09-05
Vendor
Kestra
Product
Kestra OSS
EPSS
78.8th percentile (score 0.019, as of 2026-09-16)
NVD CVSS v3.1
10 (CRITICAL)
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2026-49869

CISA short description

Kestra OSS contains an OS command injection vulnerability that could allow an unauthenticated remote attacker to create and execute arbitrary workflows without credentials.

Required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

NVD description

Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, AuthenticationFilter in Kestra OSS uses request.getPath().endsWith("/configs") to whitelist the public configuration endpoint from Basic Auth. Because the check is a suffix match rather than an exact path match, any API path whose last segment is configs bypasses authentication entirely. An unauthenticated remote attacker can exploit this to create and execute arbitrary workflows without credentials. Because Kestra ships with script execution plugins (plugin-script-shell, plugin-script-python, etc.) enabled by default, this directly results in unauthenticated Remote Code Execution as root inside the Kestra worker container. This vulnerability is fixed in 1.0.45 and 1.3.21.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.