A LLM application leveraging XMLToolMessage
class may be exposed to untrusted XML input that could result in DoS and/or exposing local files with sensitive information.
XMLToolMessage
uses lxml
without safeguards:
https://github.com/langroid/langroid/blob/df6227e6c079ec22bb2768498423148d6685acff/langroid/agent/xmltoolmessage.py#L51-L52
lxml
is vulnerable to quadratic blowup attacks and processes external entity declarations for local files by default.
Check here: https://pypi.org/project/defusedxml/#python-xml-libraries
A typical Quadratic blowup XML payload looks like this:
<!DOCTYPE bomb [
<!ENTITY a "aaaaaaaaaa">
<!ENTITY b "&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;">
<!ENTITY c "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
]>
<bomb>&c;</bomb>
Here, &a; expands to 10 characters, &b; expands to 100, and &c; expands to 1000, causing exponential memory usage and potentially crashing the application.
Langroid 0.53.4 initializes XMLParser
with flags to prevent XML External Entity (XXE), billion laughs, and external DTD attacks by disabling entity resolution, DTD loading, and network access.
https://github.com/langroid/langroid/commit/36e7e7db4dd1636de225c2c66c84052b1e9ac3c3
{ "nvd_published_at": "2025-05-05T20:15:21Z", "cwe_ids": [ "CWE-611" ], "severity": "HIGH", "github_reviewed": true, "github_reviewed_at": "2025-05-05T20:40:44Z" }