CVE-2025-6985
highpriority · track · 0EPSS 0.005 · 43 %ileEUUSEPSS · scored 2026-10-28
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.
cvss
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ssvc
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weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-m42m-m8cr-8m58LangChain Text Splitters is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing2025-10-06ghsa · osvUS
The HTMLSectionSplitter class in langchain-text-splitters 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.
- PYSEC-2026-1520LangChain Text Splitters is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing2026-07-07vendor · osvUS
The HTMLSectionSplitter class in langchain-text-splitters 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.
also known as (6)
Other names and identifiers for this entity.
sources
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references (5)
External citations — patches, advisories, analysis.
- https://github.com/langchain-ai/langchainPatchcnnvd
- https://huntr.com/bounties/cf78abbb-df3b-43de-b6ee-132b73ff8331cnnvd
- https://vigilance.fr/vulnerability/langchain-text-splitters-external-XML-entity-injection-via-HTMLSectionSplitter-48563cnnvd
- https://huntr.com/bounties/cf78abbb-df3b-43de-b6ee-132b73ff8331enisa_euvd
- https://huntr.com/bounties/cf78abbb-df3b-43de-b6ee-132b73ff8331nvd
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