CVE-2026-117341 in Octopus Server
Summary
by MITRE • 10/27/2026
In affected versions of Octopus Server, creating a user invitation writes the invitation code to the audit event log. When the invitation is linked to a space, a user in that space with appropriate permissions could read the code from the audit event. Successfully exploiting this by redeeming the unclaimed invitation could allow the user to escalate privileges however this is dependant on the permissions assigned for the invited user.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified in Octopus Server represents a critical information disclosure flaw within its authentication and access control subsystem, specifically concerning the handling of user invitations. In affected versions, when an administrator creates a new user invitation, the system generates a unique code required to complete the registration process. This code is intended for secure transmission via email or other out-of-band channels to the prospective user. However, due to improper data sanitization and logging practices, this sensitive invitation code is written in plaintext directly into the audit event log. The audit logs are designed to provide an immutable record of administrative actions for compliance and troubleshooting purposes, but they often possess broader read access permissions than intended for highly sensitive credentials or tokens. This architectural oversight creates a direct path for unauthorized data exfiltration within the application's internal trust boundary.
The operational impact of this vulnerability is significant because it undermines the confidentiality guarantees expected in secure identity management systems. An attacker who gains access to an account with permission to view audit logs can retrieve these invitation codes without needing to exploit any further vulnerabilities or bypass additional authentication mechanisms. This effectively neutralizes the security control intended by requiring a secret token for user onboarding. The severity of the exploitation is contingent upon the permissions assigned to the invited user, but even if the target role has limited initial privileges, the ability to create new accounts with arbitrary roles can lead to severe privilege escalation. If an attacker creates multiple invitations and assigns them high-privilege roles such as Administrator or Space Owner before redeeming them themselves, they can achieve full control over the Octopus Server instance. This allows for complete compromise of the CI/CD pipeline infrastructure managed by the server, potentially leading to further lateral movement within the organization's network.
From a classification perspective, this vulnerability aligns with CWE-209: Generation of Error Message Containing Sensitive Information and CWE-532: Insertion of Sensitive Information into Log File. The root cause is a failure to sanitize sensitive data before logging it, which violates fundamental principles of secure coding practices regarding the handling of secrets. In terms of adversary behavior, this flaw facilitates initial access and privilege escalation tactics described in the MITRE ATT&CK framework under T1078: Valid Accounts and specifically relates to techniques where attackers leverage existing valid accounts with elevated privileges to harvest credentials or tokens that grant further access. The exploitation does not require complex payload delivery or remote code execution vectors, making it a low-effort, high-impact vulnerability for any insider threat actor or external attacker who has achieved initial foothold through other means such as phishing or weak password authentication on an account with log viewing rights.
Mitigation strategies must address both the immediate exposure and the underlying architectural flaw. The most effective remediation is to ensure that sensitive data, including invitation codes, API keys, and passwords, are never written to audit logs in plaintext. If logging of such events is necessary for compliance or debugging purposes, the system should either omit these fields entirely or apply strong cryptographic hashing with a salt so that the original value cannot be reversed by anyone except authorized security personnel through specific forensic tools not exposed via standard UI access. Additionally, organizations should implement strict role-based access control (RBAC) policies to limit who can view audit logs, ensuring that only senior administrators have this privilege and even then, sensitive fields are masked or redacted in the interface. Regular audits of log contents and automated scanning for sensitive data patterns in log files can help detect similar misconfigurations across other systems within the infrastructure. Updating Octopus Server to a patched version where these logging practices have been corrected is essential to restore security integrity.