CVE-2026-59796 in TeamCity
Summary
by MITRE • 07/10/2026
In JetBrains TeamCity before 2026.1.2 pipeline modification was possible due to improper permission checks
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Analysis
by VulDB Data Team • 07/10/2026
The vulnerability in JetBrains TeamCity prior to version 2026.1.2 represents a critical access control flaw that allowed unauthorized users to modify pipeline configurations through inadequate permission validation mechanisms. This issue stems from insufficient authorization checks within the application's pipeline management system, enabling malicious actors or compromised users with limited privileges to manipulate build pipelines and potentially disrupt continuous integration processes.
The technical root cause of this vulnerability lies in the application's failure to properly enforce access controls when processing pipeline modification requests. Specifically, the system did not adequately validate whether authenticated users possessed the necessary administrative or modification permissions before allowing pipeline changes to be applied. This weakness creates an avenue for privilege escalation and unauthorized configuration alterations that could compromise the integrity of the entire build infrastructure.
From an operational perspective, this vulnerability presents significant risks to organizations relying on TeamCity for their CI/CD workflows. Attackers could exploit this flaw to inject malicious code into pipelines, redirect build outputs to unauthorized destinations, or disable critical build steps that ensure software quality assurance. The impact extends beyond immediate pipeline corruption to potentially compromise downstream systems and introduce security vulnerabilities throughout the development lifecycle.
The vulnerability aligns with CWE-284 Access Control Issues, specifically addressing improper access control mechanisms within the application's permission system. This weakness facilitates unauthorized modifications through insufficient authorization checks that should normally prevent users from altering pipeline configurations without proper credentials or elevated privileges. Organizations using affected TeamCity versions face potential exposure to supply chain attacks and continuous integration compromise scenarios.
Mitigation strategies should prioritize immediate upgrade to TeamCity version 2026.1.2 or later, which implements proper permission validation for pipeline modifications. Security administrators should also review existing user permissions and implement the principle of least privilege, ensuring that only authorized personnel possess pipeline modification capabilities. Additional monitoring should be implemented to detect unauthorized pipeline changes and establish incident response procedures for potential exploitation attempts.
The ATT&CK framework categorizes this vulnerability under T1078 Valid Accounts and T1546 Persistence, as it enables adversaries to maintain access through compromised accounts and potentially establish persistent modifications to build processes. Organizations should also consider implementing additional security controls such as pipeline integrity checks, code signing requirements, and automated monitoring of configuration changes to prevent exploitation of similar access control weaknesses in other CI/CD systems.
Security teams should conduct comprehensive audits of their TeamCity installations to identify any potential exploitation attempts and ensure proper implementation of access control measures. Regular security assessments of CI/CD environments are essential to maintain protection against unauthorized pipeline modifications and maintain the integrity of automated software delivery processes.