Description

Label Studio is an open source data labeling tool. Prior to version 1.16.0, Label Studio's `/projects/upload-example` endpoint allows injection of arbitrary HTML through a `GET` request with an appropriately crafted `label_config` query parameter. By crafting a specially formatted XML label config with inline task data containing malicious HTML/JavaScript, an attacker can achieve Cross-Site Scripting (XSS). While the application has a Content Security Policy (CSP), it is only set in report-only mode, making it ineffective at preventing script execution. The vulnerability exists because the upload-example endpoint renders user-provided HTML content without proper sanitization on a GET request. This allows attackers to inject and execute arbitrary JavaScript in victims' browsers by getting them to visit a maliciously crafted URL. This is considered vulnerable because it enables attackers to execute JavaScript in victims' contexts, potentially allowing theft of sensitive data, session hijacking, or other malicious actions. Version 1.16.0 contains a patch for the issue.

Classification

CVE ID: CVE-2025-25296

CVSS Base Severity: MEDIUM

CVSS Base Score: 6.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected Products

Vendor: HumanSignal

Product: label-studio

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 11.99% (scored less or equal to compared to others)

EPSS Date: 2025-03-15 (when was this score calculated)

References

https://github.com/HumanSignal/label-studio/security/advisories/GHSA-wpq5-3366-mqw4
https://github.com/HumanSignal/label-studio/commit/8cf6958e1e27ef6a03ed287e674470975d340885

Timeline