CVE-2026-49869 kestra · kestra

Kestra: Unauthenticated Remote Code Execution via Authentication Bypass in `AuthenticationFilter`

Vulnerability at a glance

Severity, exploitation likelihood & attack requirements

CVSS v3.1 severity
10.0Critical
EPSS · exploitation likelihood
2.095% Probability within 30 daysPercentile 81.5
EPSS trend
Unchanged Since 2026-10-19
Known exploitation
Known exploited CISA KEV catalog
Attack vector
NetworkRemotely reachable
Attack complexity
LowFewer obstacles to exploitation
Privileges required
NoneNo authentication required
User interaction
NoneNo user action needed
Exploit availability & maturity
Not scored Exploit reference available No explicit exploit maturity assessment View exploit evidence
How to read the colors & trend
Higher exposureElevatedModerateLower exposureUnknown / unassessed

CVSS colors follow its reported severity. Attack-factor colors describe each requirement, not an overall risk rating. Gray also covers absence from KEV; absence does not establish safety.

EPSS display bands: below 1% blue, 1–10% amber, 10–50% orange, 50% and above red. These are presentation bands, not FIRST severity categories. The trend compares daily EPSS probabilities, not percentile ranks; “pp” means percentage points. The sparkline shows relative movement, with its vertical scale fitted to the observed scores.

Already protected by existing Atomicorp rules No new CVE-specific rule required.

Atomicorp ModSecurity protection

Protected by Atomicorp rules

Atomicorp ModSecurity rules block attacks exploiting this vulnerability. Keep your rules current.

By targeting underlying attack techniques and CWE weakness classes, existing rules can protect against newly disclosed vulnerabilities. Rule changes are regression-tested against attack and false-positive corpora.

12 rules identified Verified 2026-09-06 View rules & research details →

WAF protection does not change the CVSS or EPSS score. Keep your software patched and your Atomicorp rules current.

CISA SSVC assessment

CISA ADP · Assessed 2026-09-02 · SSVC 2.0.3

Exploitation
Active exploitation
Automatable
Yes
Technical Impact
Total

Stakeholder-Specific Vulnerability Categorization records CISA’s assessment of exploitation, automation, and technical impact. “None reported” reflects the assessment date; it does not establish that no exploit exists. View SSVC source details.

On this page

CVE Details

Technical vulnerability details · CVSS assessments, exploit evidence & CPE data

CVSS assessments

CVSS v3.1 · security-advisories@github.com

  • Base score: 10.0
  • Base severity: CRITICAL
  • Exploitability subscore: 3.9
  • Impact subscore: 6.0
  • Assessment type: Secondary
  • Source identifier: security-advisories@github.com
  • Full vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
    • Attack vector: Network
    • Attack complexity: Low
    • Privileges required: None
    • User interaction: None
    • Scope: Changed
    • Confidentiality impact: High
    • Integrity impact: High
    • Availability impact: High
  • Exploit maturity: Not scored

Exploitability and impact subscores describe the vulnerability’s technical characteristics. Exploit maturity describes the reported state of exploitation; these are separate measures.

Assessment source: NVD record · CVE record

CISA SSVC assessments

These are CISA’s published decision points at the assessment time. They are not a complete organization-specific prioritization decision.

  • Provider: CISA ADP

  • Provider identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

  • SSVC version: 2.0.3

  • Role: CISA Coordinator

  • Assessment timestamp: 2026-09-02T17:44:16.457290Z

  • Exploitation: active

  • Automatable: yes

  • Technical Impact: total

  • Source: CISA ADP in the CVE record

  • Provider: CISA ADP

  • Provider identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

  • SSVC version: 2.0.3

  • Role: CISA Coordinator

  • Assessment timestamp: 2026-09-01T00:00:00+00:00

  • Exploitation: active

  • Automatable: yes

  • Technical Impact: total

  • Source: CISA ADP in the CVE record

Exploit references

The CVE source data tags these references as exploits. A reference alone does not establish reliability or active exploitation.

Vulnerable CPE configurations

  • cpe:2.3:a:kestra:kestra:*:*:*:*:*:*:*:*
    • Version end (exclusive): 1.0.45
    • NVD match criteria ID: ADC0ED79-69EF-4A2A-9F07-4791ED97124F
  • cpe:2.3:a:kestra:kestra:*:*:*:*:*:*:*:*
    • Version start (inclusive): 1.1.0
    • Version end (exclusive): 1.3.21
    • NVD match criteria ID: 73FD0092-9076-4F1C-9B93-E59C09D30E21

Vulnerability 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.

  1. Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (340014 , 340023 , 340029 , 340193 , 344360 , 344361 , 344363 , 344364 , 344366 , 344370 , 347009 , 393655 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.

  2. Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.

    • Affected versions: kestra-io kestra version < 1.0.45.
    • Affected versions: kestra-io kestra version >= 1.1.0, < 1.3.21.
    • No specific CNA/vendor solution or workaround is included in the current CVE Record . Review the vendor’s security advisories and supported-release guidance before making changes.
    • CISA KEV 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 KEV federal remediation due date: 2026-09-05

  3. Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.

Research Notes

Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.

Public Vulnerability References

Test or Research Source

  • Source: Atomicorp AI Research Framework
  • Tags: cve, derived, rce, waf-probe

Research Note Context

This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.

Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.

Learn More

Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.

Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:

  • Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
  • Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
  • Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
  • Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
  • Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.

For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ .