XXE in Lxml
CVE-2026-41066
lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.0, using either of the two parsers in the default configuration (with resolve_entities=True) allows untrusted XML input to read local files. Setting the resolve_entities option explicitly to resolve_entities='internal' or resolve_entities=False disables the local file access. This vulnerability is fixed in 6.1.0.
Vulnerability class: XXE (XML External Entity)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 23.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Lxml — versions < 6.1.0
Weakness classification (CWE)
References
- github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw (Mitigation, Vendor Advisory)
- bugs.launchpad.net/lxml/+bug/2146291 (Exploit, Third Party Advisory, Issue Tracking)
Frequently asked questions
- What is CVE-2026-41066?
- CVE-2026-41066 is a high-severity vulnerability in Lxml, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 7.5/10. Published 2026-04-24.
- How severe is CVE-2026-41066?
- High severity. CVSS v3 base score is 7.5 out of 10.