CVE-2026-14814 in GitLab
Summary
by MITRE • 10/13/2026
GitLab has remediated an issue in GitLab CE/EE affecting all versions before 19.2.8, 19.3 before 19.3.5, and 19.4 before 19.4.2 that, under certain conditions, could have allowed a user to poison cached responses for raw repository files, causing targeted users' CI/CD pipelines to execute specially crafted content and potentially exposing protected environment variables, due to improper validation of repository references.
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Analysis
by VulDB Data Team • 10/13/2026
GitLab has addressed a critical security vulnerability impacting all versions prior to 19.2.8, 19.3 before 19.3.5, and 19.4 before 19.4.2. This flaw stems from improper validation of repository references within the platform's caching mechanism for raw repository files. The core technical issue involves a cache poisoning attack vector where an attacker can manipulate cached responses associated with specific file paths in a GitLab project. By exploiting this weakness, it is possible to substitute legitimate content stored in the cache with maliciously crafted data without directly modifying the underlying git repository history in a way that would be immediately obvious through standard review processes.
The operational impact of this vulnerability is severe because it targets the integrity of continuous integration and deployment pipelines. When targeted users or automated systems retrieve raw file contents, they may receive poisoned cached responses instead of the actual source code or configuration files intended by the repository maintainers. If these retrieved files are subsequently executed within CI/CD jobs, such as shell scripts, build configurations, or dependency manifests containing malicious payloads, it leads to remote code execution on the runner infrastructure. This bypasses traditional security controls that rely solely on verifying commit signatures or branch protection rules, as the attack exploits the intermediate caching layer rather than the version control system itself.
A significant consequence of this exploitation is the potential exposure of protected environment variables. CI/CD pipelines often utilize these variables to store sensitive credentials such as API keys, database passwords, and deployment tokens. When a pipeline executes poisoned content that has been injected via cache poisoning, it may inadvertently log or transmit these secrets to external attackers. This compromises not only the specific project but potentially other projects within the same GitLab instance if shared runners are used with broad access scopes, leading to widespread credential leakage across an organization's DevOps ecosystem.
This vulnerability aligns with CWE-436, which describes interpretation ambiguity in software systems where input is processed differently than intended due to lack of normalization or validation. Furthermore, it maps to the MITRE ATT&CK technique T1587.001, specifically Development Tools Compromise, as attackers can inject malicious code into build artifacts or scripts that are then distributed and executed by victims. The attack also relates to CWE-94, Improper Control of Generation of Code, where untrusted data influences the execution flow in a dangerous manner through the CI/CD pipeline context.
To mitigate this risk, organizations must upgrade their GitLab instances immediately to version 19.2.8 or later for the 19.2 series, 19.3.5 or later for the 19.3 series, and 19.4.2 or later for the 19.4 series. These updates include patches that enforce stricter validation of repository references before serving cached responses, thereby preventing cache poisoning attacks. Additionally, administrators should review recent CI/CD job logs for any signs of anomalous behavior or unauthorized access attempts during the window when vulnerable versions were in use. Implementing strict runner isolation and limiting the scope of protected variables can further reduce the blast radius if a similar vulnerability is discovered in future updates. Regular auditing of pipeline configurations and ensuring that only trusted code sources are used as inputs for build processes remain essential best practices to maintain supply chain security within DevOps environments.