CVE-2026-15387 in GitLab
Summary
by MITRE • 08/26/2026
GitLab has remediated an issue in GitLab EE affecting all versions from 19.1 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user with developer-role permissions could have influenced the execution environment of Pipeline Execution Policy enforcement jobs, due to improper handling of job dependencies.
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Analysis
by VulDB Data Team • 08/26/2026
GitLab Enterprise Edition versions prior to 19.1.7, 19.2.5, and 19.3.1 contained a security vulnerability related to the enforcement of pipeline execution policies. This flaw specifically impacts authenticated users who possess developer-level permissions within a project or group context. The core issue stems from improper handling of job dependencies during the evaluation phase of pipeline rules that dictate whether jobs are allowed to run based on predefined conditions such as branch names, tags, or variable values. When these policy enforcement mechanisms interact with complex dependency graphs among CI/CD jobs, an attacker can manipulate the sequence and execution context in ways that bypass intended security controls.
The technical nature of this vulnerability lies in how GitLab evaluates conditional logic against job dependencies before finalizing which jobs are permitted to execute under strict pipeline policies. In environments where developers have significant control over project configuration files, including .gitlab-ci.yml definitions, they can craft specific dependency chains or rule configurations that exploit ambiguities in the policy engine's decision-making process. By carefully structuring these dependencies, an authenticated developer could potentially influence which execution environment is used for critical pipeline jobs, effectively sidestepping restrictions designed to prevent unauthorized code execution or access to sensitive infrastructure resources.
From a risk perspective, this vulnerability allows for potential privilege escalation within the CI/CD ecosystem. If an attacker successfully exploits this flaw, they may gain the ability to execute arbitrary commands in environments that were supposed to be restricted by organizational security policies. This could lead to unauthorized access to secrets stored in GitLab variables, exposure of internal network resources, or injection of malicious code into downstream deployment processes. The impact is particularly severe in organizations relying heavily on automated pipelines for secure software delivery, as it undermines the integrity of their DevSecOps practices and compliance frameworks that mandate strict control over build and deploy environments.
This issue aligns with CWE-284 Improper Access Control, specifically regarding insufficient enforcement of security policies during runtime operations. It also relates to ATT&CK technique T1059 Command and Scripting Interpreter, as the exploitation could facilitate unauthorized command execution within containerized or virtualized runner environments. Furthermore, it touches upon aspects of supply chain integrity by allowing manipulation of CI/CD workflows that are critical for maintaining software trustworthiness throughout its lifecycle.
To mitigate this risk, organizations must immediately upgrade their GitLab instances to version 19.1.7, 19.2.5, or 19.3.1 and later, depending on their current release track. These versions contain the necessary patches that correct the logic errors in pipeline policy enforcement related to job dependency handling. In addition to upgrading, administrators should review existing CI/CD configurations for overly permissive rules and ensure that developer permissions are aligned with the principle of least privilege. Regular auditing of pipeline definitions and strict control over who can modify critical configuration files will further reduce the attack surface associated with such vulnerabilities.