Transformers's Improper Input Validation vulnerability can be exploited through username injection
Hugging Face Transformers versions up to 4.49.0 are affected by an improper input validation vulnerability in the image_utils.py file. The vulnerability arises from insecure URL validation using the startswith() method, which can be bypassed through URL username injection. This allows attackers to craft URLs that appear to be from YouTube but resolve to malicious domains, potentially leading to phishing attacks, malware distribution, or data exfiltration. The issue is fixed in version 4.52.1.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | transformers | < 4.52.1 | 4.52.1 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-3777
- https://github.com/huggingface/transformers/commit/4dda5f71b35fb70cf602187eef84bb17a50b9082
- https://github.com/huggingface/transformers
- https://github.com/huggingface/transformers/blame/a7d2bbaaa8aac64f7c1ee8c1421cfe84b38359a4/src/transformers/image_utils.py
- https://huntr.com/bounties/ccba0730-9248-4853-b7ff-5c20e6364f09
- https://pypi.org/project/transformers
- https://github.com/advisories/GHSA-phhr-52qp-3mj4
- CVSS vector
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-20- Platform
- Python (PyPI)
- Package
transformers- Disclosed
- 07.07.2025
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1986 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-phhr-52qp-3mj4 - CC BY 4.0
Vulnerability history: transformers
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 32
- First → latest
- 05.2023 09.2026
- Without a fix
- 9
- Exploited in attacks
- 0
Severity breakdown
- High 18
- Medium 12
- Low 2
Disclosures per year
- 2023: 3
- 2024: 4
- 2025: 20
- 2026: 5
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Transformers's Improper Input Validation vulnerability can be exploited through username injection this entry
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