LangChain's XMLOutputParser vulnerable to XML Entity Expansion
The XMLOutputParser in LangChain uses the etree module from the XML parser in the standard python library which has some XML vulnerabilities; see: https://docs.python.org/3/library/xml.html
This primarily affects users that combine an LLM (or agent) with the XMLOutputParser and expose the component via an endpoint on a web-service.
This would allow a malicious party to attempt to manipulate the LLM to produce a malicious payload for the parser that would compromise the availability of the service.
A successful attack is predicated on:
- Usage of XMLOutputParser
- Passing of malicious input into the XMLOutputParser either directly or by trying to manipulate an LLM to do so on the users behalf
- Exposing the component via a web-service
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | langchain-core | < 0.1.35 | 0.1.35 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2024-1455
- https://github.com/langchain-ai/langchain/pull/17250
- https://github.com/langchain-ai/langchain/pull/19653
- https://github.com/langchain-ai/langchain/pull/19660
- https://github.com/langchain-ai/langchain/commit/727d5023ce88e18e3074ef620a98137d26ff92a3
- https://github.com/langchain-ai/langchain
- https://huntr.com/bounties/4353571f-c70d-4bfd-ac08-3a89cecb45b6
- https://pypi.org/project/langchain-core
- https://github.com/advisories/GHSA-q84m-rmw3-4382
- CVSS vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-776- Platform
- Python (PyPI)
- Package
langchain-core- Disclosed
- 26.03.2024
- Updated
- 11.10.2026 13:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1519 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-q84m-rmw3-4382 - CC BY 4.0
Vulnerability history: langchain-core
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 9
- First → latest
- 03.2024 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 3
- Medium 3
- Low 2
Disclosures per year
- 2024: 2
- 2025: 3
- 2026: 4
-
LangChain's XMLOutputParser vulnerable to XML Entity Expansion this entry
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