CVE-2025-27621 uptrain-ai CVE debrief

Who should care

Defenders of UpTrain instances, especially those with publicly accessible APIs, should assess exposure and take steps to restrict access until a patch is available. This includes verifying exposure of UpTrain instances, restricting access to UpTrain instances until a patch is available, and monitoring for potential exploitation attempts using the default API key. Additionally, defenders should review compensating controls for exposed systems while remedi

Why it matters

CVE-2025-27621 allows unauthorized cross-origin requests to UpTrain instances using a default API key, potentially enabling privileged operations. Defenders should verify exposure, restrict access, and monitor for exploitation attempts.

• Potential unauthorized privileged operations on UpTrain instances.
• Possible cross-origin request forgery attacks.
• Need for verification of UpTrain instance exposure.
• Priority for restricting access until a patch is available.

Technical summary

The UpTrain backend creates a default user with a static username and API key in version 0.7.1 and prior. With an open CORS policy, this allows cross-origin requests with the default API key, potentially enabling unauthorized privileged operations. The vulnerability arises from the creation of a default user with a static username and API key in UpTrain, an open-source platform for evaluating and improving generative AI applications. Combined with an open CORS policy, this allows any website to make authenticated cross-origin requests to the UpTrain instance, potentially enabling arbitrary websites to perform privileged operations as if they were the default logged-in user.

Defensive priority

Defenders should prioritize verifying exposure of UpTrain instances, especially those with publicly accessible APIs, and restrict access until a patch is available.

Recommended defensive actions

• Verify exposure of UpTrain instances, especially those with publicly accessible APIs.
• Restrict access to UpTrain instances until a patch is available.
• Monitor for potential exploitation attempts using the default API key.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details about the vulnerability, including its CVSS score of 7.7 and the lack of available patches. The UpTrain backend's default user setup and open CORS policy are key factors in the vulnerability.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.