CVE-2026-44937 in SUSE Rancher Fleet
Summary
by MITRE • 07/06/2026
Potential forgery of webhook requests when using a unauthenticated webhook in SUSE Rancher Fleet 0.15 before 0.15.2, 0.14 before 0.14.6, 0.13 before 0.13.11 and 0.12 before 0.12.5 could be used by remote attackers to cause a denial of service or a downgrade attack on other repositories on the system.
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Analysis
by VulDB Data Team • 07/06/2026
This vulnerability in SUSE Rancher Fleet represents a critical security flaw that undermines the integrity of webhook authentication mechanisms within container orchestration environments. The issue affects multiple versions of the Rancher Fleet management platform, specifically targeting versions 0.15 before 0.15.2, 0.14 before 0.14.6, 0.13 before 0.13.11, and 0.12 before 0.12.5, creating a persistent security risk across various deployment scenarios. The vulnerability stems from insufficient authentication validation during webhook request processing, allowing unauthorized actors to craft and inject malicious requests that appear legitimate to the system.
The technical flaw manifests as a lack of proper signature verification or authentication checks when processing incoming webhook events. This weakness enables attackers to forge webhook requests by simply replicating the expected payload structure without requiring valid credentials or cryptographic signatures. The vulnerability maps directly to CWE-345 Insufficient Verification of Data Authenticity, which specifically addresses scenarios where systems fail to verify the authenticity of received data, and can be categorized under ATT&CK technique T1078 Valid Accounts for maintaining persistence through forged legitimate-looking requests.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential downgrade attacks that could compromise repository integrity. Remote attackers exploiting this flaw could manipulate the system's configuration or content delivery mechanisms, potentially leading to supply chain compromises where malicious code is injected into legitimate software repositories. The consequences include unauthorized modifications to deployment configurations, disruption of continuous integration workflows, and possible privilege escalation within the container orchestration environment.
Mitigation strategies should focus on implementing robust webhook authentication mechanisms including HMAC signature verification, secure token generation, and proper request validation. Organizations should immediately upgrade to patched versions of Rancher Fleet, implement network-level access controls for webhook endpoints, and establish monitoring procedures to detect anomalous webhook activity. The remediation approach aligns with security best practices outlined in NIST SP 800-53 and ISO 27001 frameworks, emphasizing the importance of input validation and authentication controls in distributed systems. Additionally, administrators should consider implementing webhook request rate limiting and anomaly detection mechanisms to further protect against exploitation attempts.