CVE-2026-89078 in GitLab
Summary
by MITRE • 09/24/2026
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 19.2 before 19.2.7, 19.3 before 19.3.3, and 19.4 before 19.4.1 that under certain conditions could have allowed an authenticated user to execute arbitrary code on the GitLab server due to a double free issue when parsing a specially crafted regular expression in a CI/CD configuration.
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Analysis
by VulDB Data Team • 09/24/2026
GitLab has addressed a critical security vulnerability affecting multiple versions of its Community Edition and Enterprise Edition, specifically impacting releases from 19.2 prior to version 19.2.7, 19.3 prior to version 19.3.3, and 19.4 prior to version 19.4.1. This flaw represents a significant security risk as it allows an authenticated user to achieve arbitrary code execution on the GitLab server under specific conditions. The vulnerability stems from improper memory management within the application's parsing logic for Continuous Integration and Continuous Deployment configurations, highlighting the dangers of complex input processing in enterprise software platforms that handle sensitive development workflows.
The technical root cause of this issue is a double free error occurring during the parsing of specially crafted regular expressions embedded within CI/CD configuration files. In C-based or memory-managed environments often used for high-performance components like GitLab's backend, a double free occurs when a program attempts to deallocate a block of memory that has already been freed. This corruption can lead to undefined behavior, which attackers frequently exploit to gain control over the execution flow of the application. By crafting a malicious regular expression payload, an authenticated user could trigger this condition during the validation or processing phase of their pipeline configuration, thereby compromising the integrity and stability of the GitLab instance.
From an operational perspective, the ability for an authenticated user to execute arbitrary code on the server is severe because it bypasses initial authentication barriers. Once inside the system with valid credentials, a malicious actor could potentially exfiltrate sensitive source code, modify deployment pipelines to inject malware into production environments, or pivot further into internal networks connected to the GitLab infrastructure. This vulnerability undermines the trust model of CI/CD platforms where users are expected to have elevated privileges for managing their projects but should not be able to compromise the underlying host system. The impact extends beyond individual project integrity to encompass the security posture of the entire organization relying on these pipelines for software delivery.
This incident aligns with common vulnerability classifications such as CWE-415, which describes Double Free vulnerabilities that can lead to arbitrary code execution or denial of service. It also relates to CWE-78, Improper Neutralization of Special Elements used in an OS Command, given the potential outcome of command injection through memory corruption techniques. In terms of adversary tactics, this vulnerability could be leveraged within MITRE ATT&CK framework categories such as Initial Access via Valid Accounts and Execution via Remote Services or Command Line Interface, allowing attackers to establish persistence and escalate privileges on compromised hosts.
To mitigate this risk, organizations running affected versions must immediately upgrade GitLab CE/EE to the patched releases: 19.2.7 for the 19.2 branch, 19.3.3 for the 19.3 branch, or 19.4.1 for the 19.4 branch. Prior to upgrading, administrators should review access logs for any suspicious activity involving CI/CD configuration changes from authenticated users who may have attempted to exploit this flaw. Additionally, implementing strict input validation and sanitization practices in custom integrations or plugins can help prevent similar issues if new vulnerabilities are discovered in the future. Regular patching cycles and monitoring of vendor security advisories remain essential components of a robust defense-in-depth strategy for maintaining secure DevOps environments.