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CVE-2026-5173 is an improper access control vulnerability in GitLab Community Edition and Enterprise Edition WebSocket connection handling. Affected versions allow an authenticated user, including a low-privilege user, to invoke unintended internal server-side methods over WebSocket connections because the WebSocket handler does not adequately restrict which methods may be called. The issue affects GitLab CE/EE versions from 16.9.6 before 18.8.9, 18.9 before 18.9.5, and 18.10 before 18.10.3. The vulnerability is classified as CWE-749 because internal functionality was exposed through a reachable interface without sufficient method-level authorization checks.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository is a small standalone Python proof-of-concept for CVE-2026-5173 targeting GitLab WebSocket/GraphQL functionality. It contains two files: a single executable Python script (CVE-2026-5173.py) and a README with usage, affected versions, and lab setup guidance. The exploit logic is straightforward: it normalizes a supplied target URL, converts it to a WebSocket endpoint by appending /-/cable, sets an Origin header matching the target, connects with the Python websockets library, subscribes to the GitLab ActionCable GraphqlChannel, and then iterates through a hardcoded list of candidate GraphQL methods. For each method it sends an ActionCable message with action=execute and a GraphQL query intended to retrieve user or node data. Responses containing "data" or "result" are treated as signs of successful unauthorized access and printed to stdout. Main capabilities: WebSocket connection to GitLab, GraphqlChannel subscription, enumeration of multiple likely sensitive GraphQL methods, and display of returned data that may include users, projects, namespaces, statistics, or internal/admin-related objects. There is no post-exploitation payload, persistence, shell, or command execution. The script is best characterized as a research PoC for unauthorized data access validation rather than a full weaponized exploit. Notable implementation detail: although the README claims support for a Personal Access Token and the CLI accepts --token, the token is never used in headers, cookies, or messages. That means authentication handling is incomplete in the actual code. Overall, this is a minimal network/web exploit PoC focused on probing GitLab's /-/cable WebSocket endpoint for unauthorized GraphQL method execution and data disclosure.
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19 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A high-severity GitLab CE/EE websocket vulnerability that could let an authenticated attacker bypass access controls and invoke unintended server-side methods.
A high-severity GitLab vulnerability that allows an authenticated attacker to execute unintended server-side commands through WebSocket connections because of improper access controls.
An improper access control vulnerability in GitLab CE/EE that could allow an authenticated user to invoke unintended server-side methods through websocket connections.
An improper access control vulnerability in GitLab CE/EE websocket connections that could allow an authenticated user to invoke unintended server-side methods.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.