Authentication bypass leading to unauthenticated RCE in Kestra OSS
CISA: Kestra OSS OS Command Injection Vulnerability
CVSS 3.1
10.0critical
EPSS
2%p79
Published
()
KEV added
AI analysis
CVE-2026-49869 is a critical (CVSS 3.1: 10.0) authentication bypass in the open-source Kestra event-driven orchestration platform: the AuthenticationFilter exempts the public configuration endpoint from Basic Auth using a suffix match (request paths ending in "/configs") rather than an exact path comparison. As a result, an unauthenticated remote attacker can call any API URL whose final path segment is "configs", which is enough 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 yields unauthenticated remote code execution as root inside the Kestra worker container. All Kestra OSS deployments prior to 1.0.45 and 1.3.21 are affected, with the greatest risk for instances whose API is reachable from the internet or untrusted networks. The flaw is being actively exploited: CISA added it to the KEV catalog on 2026-09-02 (EPSS 1.9%, percentile 79), and headlines covering the KEV batch report attackers deploying reverse shells and crypto miners.
What to do: Upgrade to Kestra 1.0.45 (for the 1.0.x line) or 1.3.21 (for the 1.3.x line), or later releases that incorporate the fix. If immediate patching is not possible, restrict network access to the Kestra API (firewall/ACL or a reverse proxy that enforces authentication for all paths, including any ending in /configs). Given active exploitation, audit instances for signs of compromise such as unexplained workflows, reverse shells, or cryptomining processes in worker containers; federal agencies must patch per CISA BOD 26-04 timelines.
Affected
Kestra OSS (kestra)
All versions prior to 1.0.45 and prior to 1.3.21; fixed in 1.0.45 and 1.3.21
Estimated exposure
moderatelikely low thousands of internet-exposed Kestra instances (estimate; no authoritative install or scan counts in source data) — Kestra is a moderately adopted open-source orchestrator that is typically self-hosted and kept on internal networks, so based on typical deployment patterns only a fraction of its install base is directly internet-exposed, plausibly on the…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
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.
CISA Known Exploited Vulnerability
Affected
Kestra Kestra OSS
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 added seven actively exploited vulnerabilities to its KEV catalog, including SonicWall SMA 1000 SSRF CVE-2026-83548, amid campaigns deploying reverse shells and crypto miners.
CISA's KEV additions cover flaws in SonicWall SMA 1000 (CVE-2026-83548, CVE-2026-83549), Sangoma Switchvox (CVE-2026-9586), JFrog Artifactory (CVE-2026-82329), Kludex Starlette (CVE-2026-48710), Kestra OSS (CVE-2026-49869) and Berri LiteLLM's MCP endpoint (CVE-2026-59822). SonicWall confirmed active exploitation of the SMA 1000 flaws, while Microsoft and Wiz reported attackers chaining LiteLLM flaws CVE-2026-42271 and CVE-2026-48710 to fingerprint hosts, steal provider API keys and deploy XMRig miners on AI infrastructure. Wiz linked exploitation of the LiteLLM chain to the Qilin ransomware group, and Microsoft detailed a Kestra compromise chain ending in cryptocurrency mining and data harvesting via exposed RAGFlow flaws.
CISA added seven actively exploited vulnerabilities to its KEV catalog, including SonicWall SMA1000 SSRF and command injection flaws.
CISA added seven vulnerabilities with evidence of active exploitation to its Known Exploited Vulnerabilities catalog on September 2, 2026. The additions cover Sangoma Switchvox SQL injection (CVE-2026-9586), Kludex Starlette request smuggling (CVE-2026-48710), Kestra OS command injection (CVE-2026-49869), BerriAI LiteLLM (CVE-2026-59822) and JFrog Artifactory (CVE-2026-82329) authentication flaws, and SonicWall SMA1000 SSRF (CVE-2026-83548) and command injection (CVE-2026-83549) vulnerabilities. Under BOD 26-04, federal civilian agencies must prioritize rapid remediation of KEV-listed vulnerabilities on publicly exposed assets.