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High, CVSS 7.5amended

LangChain Text Splitters is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing

CVE-2025-6985GHSA-m42m-m8cr-8m58

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (langchain-text-splitters 0.3.9), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
  • CVE-2025-6985: 0.51% estimated exploitation activity in the next 30 days; percentile 43.45 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-m42m-m8cr-8m58

  2. Revision 1 · created ·

    Published from osv record GHSA-m42m-m8cr-8m58

Agent brief

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# Patch Next advisory brief: CVE-2025-6985

Advisory: LangChain Text Splitters is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing
IDs: CVE-2025-6985, GHSA-m42m-m8cr-8m58
Record: https://patchnext.com/advisories/cve-2025-6985 (revision 2, source checked 26 Oct 2026, 13:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: langchain-text-splitters 0.3.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI langchain-text-splitters: affected < 0.3.9; fixed in 0.3.9

## Suggested inspection (read-only)
- `python -m pip show langchain-text-splitters`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on langchain-text-splitters.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-m42m-m8cr-8m58 (OSV record GHSA-m42m-m8cr-8m58 lists affected ranges: PyPI langchain-text-splitters >=0 <0.3.9 (fixed))
- Verified: https://github.com/advisories/GHSA-m42m-m8cr-8m58 (GitHub-reviewed advisory GHSA-m42m-m8cr-8m58 lists affected ranges: PyPI langchain-text-splitters >=0 <0.3.9)

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