CVE-2025-27621 UpTrain has a Constant Default API Key
Attackers can use a static default API key and open CORS policy to perform privileged operations on UpTrain instances from arbitrary websites.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-27621?
CVE-2025-27621 is a high-severity vulnerability in uptrain-ai uptrain, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-287
Which versions are affected by CVE-2025-27621?
How do I fix CVE-2025-27621?
No fix has been published for CVE-2025-27621 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-27621 being exploited?
There is no known exploitation of CVE-2025-27621 in the wild and no public exploit code.