CVE-2025-27621CWE-287

CVE-2025-27621

published August 17, 2026

CVSS
7.7
EPSS
0%
Percentile
38.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS
7.7 · NONE
CVSS v4.0
7.7 · 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
EPSS
0.00458 · 38.8th percentile
Weakness
CWE-287 · Improper Authentication
Published
2026-08-17T20:16Z
References (2)
EPSS history
Timeline
  • 17 AUG 15:42Z
    UpTrain has a Constant Default API Key
    cvelistv5