fix: update lxml to 6.1.0 for CVE-2026-41066 (backport #250)

[mergify]

This updates the app’s lxml dependency to the first patched release for GHSA-vfmq-68hx-4jfw / CVE-2026-41066. The advisory affects unsafe default entity resolution in iterparse() and ETCompatXMLParser().

• Dependency update

  • Raise the lxml constraint in pyproject.toml from >=4.9.3,<=6.0.2 to >=6.1.0,<7.0.0.
  • This keeps the change scoped to the minimum non-vulnerable line.

• Reachability assessment

  • Searched the codebase for the affected APIs named in the advisory: iterparse() and ETCompatXMLParser().
  • No direct usage was found.
  • The repo does use lxml.objectify.fromstring() in eu_einvoice/schematron/__init__.py, but that is outside the vulnerable code path described in the advisory.
  • Assessment: the vulnerable path is not directly reachable in the current codebase; this change primarily removes the flagged vulnerable dependency version.
  • Confidence: high, because the advisory names specific APIs and repo-wide search found no call sites.

• Resulting manifest change

  dependencies = [
    "factur-x~=3.1",
    "drafthorse~=2025.1.0",
    "saxonche>=12.5.0,<13.0.0",
    "lxml>=6.1.0,<7.0.0",
  ]

Original prompt

---

This section details the Dependabot vulnerability alert you should resolve

<alert_title>lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files</alert_title>
<alert_description>### Impact
Using either of the two parsers in the default configuration (with resolve_entities=True) allows untrusted XML input to read local files.

Patches

lxml 6.1.0 changes the default to resolve_entities='internal', thus disallowing local file access by default.

Workarounds

Setting the resolve_entities option explicitly to resolve_entities='internal' or resolve_entities=False disables the local file access.

Resources

Original report: https://bugs.launchpad.net/lxml/+bug/2146291

The default option was changed to resolve_entities='internal' for the normal XML and HTML parsers in lxml 5.0. The default was not changed for iterparse() and ETCompatXMLParser() at the time. lxml 6.1 makes the safe option the default for all parsers.</alert_description>

high
GHSA-vfmq-68hx-4jfw, CVE-2026-41066
lxml
pip
<vulnerable_versions>>= 4.9.3,<= 6.0.2</vulnerable_versions>
<patched_version>6.1.0</patched_version>
<manifest_path>pyproject.toml</manifest_path>

https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw https://bugs.launchpad.net/lxml/+bug/2146291 https://github.com/lxml/lxml/releases/tag/lxml-6.1.0 https://github.com/advisories/GHSA-vfmq-68hx-4jfw

<task_instructions>Resolve this alert by updating the affected package to a non-vulnerable version. Prefer the lowest non-vulnerable version (see the patched_version field above) over the latest to minimize breaking changes. Include a Reachability Assessment section in the PR description. Review the alert_description field to understand which APIs, features, or configurations are affected, then search the codebase for usage of those specific items. If the vulnerable code path is reachable, explain how (which files, APIs, or call sites use the affected functionality) and note that the codebase is actively exposed to this vulnerability. If the vulnerable code path is not reachable, explain why (e.g. the affected API is never called, the vulnerable configuration is not used) and note that the update is primarily to satisfy vulnerability scanners rather than to address an active risk. If the advisory is too vague to determine reachability (e.g. 'improper input validation' with no specific API named), state that reachability could not be determined and explain why. Include a confidence level in the reachability assessment (e.g. high confidence if the advisory names a specific API and you confirmed it is or is not called, low confidence if the usage is indirect and hard to trace). If no patched version is available, check the alert_description field for a Workarounds section — the advisory may describe configuration changes or usage patterns that mitigate the vulnerability without a version update. If a workaround is available, apply it and leave a code comment referencing the advisory identifier explaining it is a temporary mitigation. If neither a patch nor a workaround is available, explain in the PR description why the alert cannot be resolved automatically so a human reviewer can take over. Inspect the repository to determine which package manager is used (e.g. lock files, config files, build scripts) and use that tooling to perform the update — do not edit lock files directly. If the version constraint in the manifest (e.g. package.json, Gemfile, pyproject.toml) caps the version below the fix, update the constraint first. For transitive dependencies, determine whether it is simpler to update the direct dependency that pulls in the vulnerable package or to update the transitive dependency directly, and choose the least disruptive approach. If upgrading to fix the vulnerability forces a major version bump or known breaking changes, review the changelog or release notes, then audit the codebase for usage of affected APIs and fix any breaking changes that are found. If the package manager fails to resolve dependencies (e.g. peer dependency conflicts, incompatible engine constraints), document the error in the PR description rather than attempting increasingly complex workarounds. After updating, check the lock file to confirm the package no longer resolves to a version in the vulnerable range. Keep changes minimal and tightly scoped. Ensure tests, build, type checking, and linting all pass after your changes. If there are any test, lint, or typechecking failures, investigate whether they are caused by the update and fix them if so — do not leave broken tests in the PR. If they were already present before the update, note them in the PR description so a human reviewer can assess whether they are related.</task_instructions>

• Resolves alyf-de/eu_einvoice alert Error reading Payment Terms from test documents #1

  ---

  This is an automatic backport of pull request fix: update lxml to 6.1.0 for CVE-2026-41066 #250 done by Mergify.

[greptile-apps]

Greptile Summary

Updates the lxml dependency constraint from >=4.9.3,<=6.0.2 to >=6.1.0,<7.0.0 to remediate CVE-2026-41066 (GHSA-vfmq-68hx-4jfw), which allows XXE attacks via iterparse() and ETCompatXMLParser() when resolve_entities=True. The codebase only calls lxml.objectify.fromstring() and imports lxml.etree.XMLSyntaxError — neither of the affected APIs — so this is primarily a dependency hygiene fix.

Confidence Score: 5/5

Safe to merge — single-line constraint bump to the known-good patched version with no breaking API changes needed in the codebase.

The change is a one-line version constraint update. Repo-wide search confirms no usage of the vulnerable APIs (iterparse, ETCompatXMLParser). The new range >=6.1.0,<7.0.0 targets the minimum patched release and caps the major version for stability. No other files are touched.

No files require special attention.

Important Files Changed

Filename	Overview
pyproject.toml	Raises lxml lower bound to 6.1.0 (first patched release) and tightens upper bound to <7.0.0; change is minimal, correct, and scoped only to the vulnerable dependency.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[XML Input] --> B[get_validation_report\nPySaxonProcessor / XSLT]
    B --> C[SVRL report bytes]
    C --> D[extract_failed_asserts\nlxml.objectify.fromstring]
    D --> E[errors / warnings list]

    F[lxml APIs in codebase] --> G[objectify.fromstring ✅ safe]
    F --> H[etree.XMLSyntaxError ✅ safe, import only]

    I[Vulnerable APIs - CVE-2026-41066] --> J[iterparse ❌ not used]
    I --> K[ETCompatXMLParser ❌ not used]

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_{Reviews (1): Last reviewed commit: "fix: update lxml to 6.1.0 for CVE-2026-4..." | Re-trigger Greptile}