XXE Vulnerability in langchain-ai/langchain (langchain-ai langchain-ai/langchain)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.51 % · percentile 43 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- @huntr_ai
- NVD status
- Deferred
Description
The HTMLSectionSplitter class in langchain-text-splitters version 0.3.8 is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing. This vulnerability arises because the class allows the use of arbitrary XSLT stylesheets, which are parsed using lxml.etree.parse() and lxml.etree.XSLT() without any hardening measures. In lxml versions up to 4.9.x, external entities are resolved by default, allowing attackers to read arbitrary local files or perform outbound HTTP(S) fetches. In lxml versions 5.0 and above, while entity expansion is disabled, the XSLT document() function can still read any URI unless XSLTAccessControl is applied. This vulnerability allows remote attackers to gain read-only access to any file the LangChain process can reach, including sensitive files such as SSH keys, environment files, source code, or cloud metadata. No authentication, special privileges, or user interaction are required, and the issue is exploitable in default deployments that enable custom XSLT.
Weaknesses (CWE)
- CWE-611 — Improper Restriction of XML External Entity Reference
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.0 | HIGH 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | @huntr_ai |
| CVSS 3.0 | HIGH 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD · security@huntr.dev (Secondary) |
Advisories
- GHSA-m42m-m8cr-8m58 — LangChain Text Splitters is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing
- PYSEC-2026-1520 — LangChain Text Splitters is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing
European references
- ENISA EUVD · EUVD-2025-31884
- GCVE · GCVE-0-2025-6985
Affected products
| Product | Versions |
|---|---|
| langchain-ai · langchain-ai/langchain | affected unspecified ≤ latest |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |