XML External Entity injection in Lxml - CVE-2026-41066
Published: April 20, 2026
Vulnerability identifier: #VU126548
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-41066
CWE-ID: CWE-611
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Lxml
Affected software:
Lxml
Lxml
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper restriction of xml external entity reference in iterparse() and ETCompatXMLParser() when parsing untrusted XML input. A remote attacker can send specially crafted XML input to disclose sensitive information.
The issue occurs when these parsers are used in the default configuration with resolve_entities=True.
How to mitigate CVE-2026-41066
Install security update from vendor's website.