GitLab Warns of Active Exploitation of Critical GraphQL Flaw

GitLab flaw CVE-2026-19478 is now under active exploitation, allowing unauthenticated attackers to modify or delete public projects.

WatchTowr researchers warn of active exploitation of critical GitLab flaw CVE-2026-19478 (CVSS score of 9.4). This week, GitLab pushed out an emergency patch to address this flaw, which could let an attacker with zero credentials remotely modify or delete public projects and user data.

“GitLab has remediated an issue that under certain conditions could allow an unauthenticated user to remotely modify or delete public projects and user data via a GraphQL directive.” reads the advisory.

GitLab issued an emergency patch on August 17, five days after its regular update. The vulnerability impacts only self-managed installations, users should upgrade to versions  19.2.4, 19.1.6, 19.0.8, and 18.11.11.

There’s a gap worth flagging for anyone still sitting on an older release. The available patches don’t cover the 18.2 through 18.10 branches, even though those versions technically fall inside the affected range. If you’re running anything in that window, staying put isn’t really an option; you’ll need to upgrade to a patched branch entirely rather than waiting for a fix that isn’t coming for your current one.

hiimguardian reported the flaw through the company HackerOne bug bounty program.

Organizations should urgently patch internet-facing GitLab servers. Until they can update, they should restrict unauthenticated access to /api/graphql, disable public repositories where possible, and check logs for requests containing @gl_introduced.

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Pierluigi Paganini

(SecurityAffairs – hacking, CVE-2026-19478)