CVE-2026-4372
Arbitrary Remote Code Execution via `_attn_implementation_internal` Config Injection in huggingface/transformers
Description
A critical remote code execution vulnerability exists in all versions of the HuggingFace transformers library prior to version 5.3.0. The vulnerability allows an attacker to craft a malicious `config.json` file containing the `_attn_implementation_internal` field set to an attacker-controlled HuggingFace Hub repository ID. When a victim loads this model using the standard `AutoModelForCausalLM.from_pretrained()` API, the library downloads and executes arbitrary Python code from the attacker's repository with the victim's full OS privileges. This issue arises due to unfiltered deserialization of configuration attributes, insufficient sanitization of internal fields, and unsandboxed execution of downloaded kernels. The vulnerability bypasses the `trust_remote_code` security mechanism, is invisible to the victim, and exploits the standard documented usage pattern, making it particularly severe. Users are advised to upgrade to version 5.3.0 or later to mitigate this issue.
INFO
Published Date :
May 24, 2026, 2:16 p.m.
Last Modified :
June 4, 2026, 6:24 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.0 | HIGH | MITRE-CVE | ||||
| CVSS 3.0 | HIGH | [email protected] |
Solution
- Update HuggingFace transformers library to version 5.3.0.
- Verify model configurations before loading.
Public PoC/Exploit Available at Github
CVE-2026-4372 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-4372.
| URL | Resource |
|---|---|
| https://github.com/huggingface/transformers/commit/a7f8e7ff37d87d1a1a0c8cf607971c607741452f | Patch |
| https://huntr.com/bounties/1f693a6e-6836-4b8b-a0bd-ca036fba8884 | Exploit Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-4372 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-4372
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-4372 vulnerability anywhere in the article.
-
CybersecurityNews
Critical Hugging Face Transformers Vulnerability Enables Remote Code Execution Attacks
A newly disclosed critical vulnerability in the HuggingFace Transformers library, tracked as CVE-2026-4372, allows attackers to achieve remote code execution (RCE) through malicious model configuratio ... Read more
The following table lists the changes that have been made to the
CVE-2026-4372 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 04, 2026
Action Type Old Value New Value Added CWE CWE-502 Added CPE Configuration OR *cpe:2.3:a:huggingface:transformers:*:*:*:*:*:*:*:* versions up to (excluding) 5.3.0 Added Reference Type huntr.dev: https://github.com/huggingface/transformers/commit/a7f8e7ff37d87d1a1a0c8cf607971c607741452f Types: Patch Added Reference Type huntr.dev: https://huntr.com/bounties/1f693a6e-6836-4b8b-a0bd-ca036fba8884 Types: Exploit, Third Party Advisory -
New CVE Received by [email protected]
May. 24, 2026
Action Type Old Value New Value Added Description A critical remote code execution vulnerability exists in all versions of the HuggingFace transformers library prior to version 5.3.0. The vulnerability allows an attacker to craft a malicious `config.json` file containing the `_attn_implementation_internal` field set to an attacker-controlled HuggingFace Hub repository ID. When a victim loads this model using the standard `AutoModelForCausalLM.from_pretrained()` API, the library downloads and executes arbitrary Python code from the attacker's repository with the victim's full OS privileges. This issue arises due to unfiltered deserialization of configuration attributes, insufficient sanitization of internal fields, and unsandboxed execution of downloaded kernels. The vulnerability bypasses the `trust_remote_code` security mechanism, is invisible to the victim, and exploits the standard documented usage pattern, making it particularly severe. Users are advised to upgrade to version 5.3.0 or later to mitigate this issue. Added CVSS V3 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-1066 Added Reference https://github.com/huggingface/transformers/commit/a7f8e7ff37d87d1a1a0c8cf607971c607741452f Added Reference https://huntr.com/bounties/1f693a6e-6836-4b8b-a0bd-ca036fba8884