{"id":"CVE-2026-41066","aliases":["GHSA-vfmq-68hx-4jfw","PYSEC-2026-87"],"url":"https://o3.security/vulnerability/CVE-2026-41066","summary":"lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files","details":"### Impact\nUsing either of the two parsers in the default configuration (with `resolve_entities=True`) allows untrusted XML input to read local files.\n\n### Patches\nlxml 6.1.0 changes the default to `resolve_entities='internal'`, thus disallowing local file access by default.\n\n### Workarounds\nSetting the `resolve_entities` option explicitly to `resolve_entities='internal'` or `resolve_entities=False` disables the local file access.\n\n### Resources\nOriginal report: https://bugs.launchpad.net/lxml/+bug/2146291\n\nThe 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.","published":"2026-04-24T16:45:19.617Z","modified":"2026-08-12T03:51:45.950424680Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":{"score":0.00324,"percentile":0.25586,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"lxml","fixedVersion":"6.1.0"}],"fix":null,"references":[{"type":"WEB","url":"https://bugs.launchpad.net/lxml/+bug/2146291"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41066.json"},{"type":"ADVISORY","url":"https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41066"},{"type":"PACKAGE","url":"https://github.com/lxml/lxml"},{"type":"WEB","url":"https://github.com/lxml/lxml/releases/tag/lxml-6.1.0"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2026-87.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:45.950424680Z"}}