Description

With the following crawler configuration:

```python
from bs4 import BeautifulSoup as Soup

url = "https://example.com"
loader = RecursiveUrlLoader(
url=url, max_depth=2, extractor=lambda x: Soup(x, "html.parser").text
)
docs = loader.load()
```

An attacker in control of the contents of `https://example.com` could place a malicious HTML file in there with links like "https://example.completely.different/my_file.html" and the crawler would proceed to download that file as well even though `prevent_outside=True`.

https://github.com/langchain-ai/langchain/blob/bf0b3cc0b5ade1fb95a5b1b6fa260e99064c2e22/libs/community/langchain_community/document_loaders/recursive_url_loader.py#L51-L51

Resolved in https://github.com/langchain-ai/langchain/pull/15559

Classification

CVE ID: CVE-2024-0243

CVSS Base Severity: LOW

CVSS Base Score: 3.7

CVSS Vector: CVSS:3.0/AV:L/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:N

Affected Products

Vendor: langchain-ai

Product: langchain-ai/langchain

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.13% (probability of being exploited)

EPSS Percentile: 48.6% (scored less or equal to compared to others)

EPSS Date: 2025-03-14 (when was this score calculated)

References

https://huntr.com/bounties/370904e7-10ac-40a4-a8d4-e2d16e1ca861
https://github.com/langchain-ai/langchain/commit/bf0b3cc0b5ade1fb95a5b1b6fa260e99064c2e22
https://github.com/langchain-ai/langchain/pull/15559

Timeline