Langroid, XXE Injection, CVE-2025-XXXX (High)

Langroid’s `XMLToolMessage` class processes XML input without proper safeguards, enabling XML External Entity (XXE) injection. Attackers can submit malicious XML payloads containing external entity references, leading to denial-of-service (DoS) via quadratic blowup attacks or unauthorized file access. The `lxml` parser, by default, resolves entities and loads external DTDs, allowing attackers to craft payloads like:

<!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>

This exhausts memory due to exponential expansion. Additionally, XXE can read local files via `file://` URIs.

DailyCVE Form:

Platform: Langroid
Version: <0.53.4
Vulnerability: XXE Injection
Severity: High
Date: 2025-05-05

What Undercode Say:

Exploit:

1. Craft XML with nested entities for DoS:

payload = """<!DOCTYPE bomb [<!ENTITY a "A" 10>...]>"""

2. Exfiltrate files via XXE:

<!DOCTYPE leak [<!ENTITY xxe SYSTEM "file:///etc/passwd">]>

Protection:

1. Update Langroid to >=0.53.4.

2. Use `defusedxml`:

from defusedxml.lxml import fromstring

3. Secure `XMLParser` flags:

parser = XMLParser(resolve_entities=False, no_network=True)

Detection:

1. Scan for `XMLToolMessage` usage.

2. Monitor memory spikes during XML parsing.

Mitigation Commands:

pip install langroid==0.53.4

Code Snippet (Secure Parsing):

from lxml import etree
parser = etree.XMLParser(resolve_entities=False, dtd_validation=False)
safe_xml = etree.fromstring(xml_input, parser=parser)