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Fencer Vulns
medium 6.1

CVE-2025-25296 json

Label Studio allows Cross-Site Scripting (XSS) via GET request to `/projects/upload-example` endpoint

published 2025-02-14 20 mo ago modified 2026-07-07 4 mo ago also EUVD-2025-4106 , GHSA-wpq5-3366-mqw4 , PYSEC-2026-1504

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known, plus a Nuclei check

Summary

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.

Patch / fix

  • pypi label-studio 1.16.0
  • humansignal label_studio 1.16.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
20 mo ago

Exploit prediction

1.90% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Label Studio < 1.16.0 - Cross-Site Scripting nuclei detection template
  • github.com https://github.com/HumanSignal/label-studio/security/advisories/GHSA-wpq5-3366-mqw4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
OSV 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi label-studio
<1.16.0
1.16.0

Affected products

  • HumanSignal label-studio

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.