CVE-2026-49869: Kestra Kestra OSS

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run Kestra Kestra OSS. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-09-02, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-09-05; treat that as the outer limit, not the target.
EPSS 2.1%, percentile 81: FIRST’s model estimates a 2.1% chance of exploitation activity in the next 30 days, higher than 81% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
Editorial verdict: Act now. Kestra CVE-2026-49869: Exploited Unauthenticated RCE — If you run Kestra OSS below 1.0.45 or 1.3.21 and anyone untrusted can reach its API, assume it is compromised: upgrade, then rotate every secret the workers could see.

What it is

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.

CISA’s summary

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

Weakness type: CWE-78, CWE-184, CWE-287, CWE-918.

Product: Kestra Kestra OSS · Assigned by: GitHub_M · Published: 2026-06-26

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
kestra-io	kestra	< 1.0.45, >= 1.1.0, < 1.3.21

Severity scores

Scored by	CVSS	Score	Vector
GitHub_M	3.1	10 Critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

Attack vector: network (remotely reachable)
Attack complexity: low
Privileges required: none (no login)
User interaction: none
Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2026-09-02; federal due date 2026-09-05. Known ransomware use: Unknown.
CISA 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.
CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 2.10% probability of exploitation activity in the next 30 days; percentile 81.

Timeline

2026-06-03 — erroneo.us brief: Kestra CVE-2026-49869: Exploited Unauthenticated RCE
2026-06-26 — CVE record published by GitHub_M
2026-09-02 — Added to CISA’s Known Exploited Vulnerabilities catalog
2026-09-03 — CVE record last updated
2026-09-05 — CISA remediation deadline for US federal agencies

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.