CVE-2026-41066 | lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files

Exp

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.

Published: 2026-04-24 Last update: 2026-04-27 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-41066 is rated Exploit Available (51.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.26%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-41066

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-41066

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.06% 0.26% +0.20%
2 2026-06-05 0.03% 0.06% +0.03%
3 2026-04-25 — 0.03% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-41066

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-41066

GitHub Security Advisory for CVE-2026-41066

GHSA-vfmq-68hx-4jfw · Severity: high · Ecosystem: pip — lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files

OS Trackers for CVE-2026-41066

vendor priority summary link
debian not yet assigned CVE-2026-41066 not yet assigned priority: Debian including 1 source packages (lxml), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-41066
suse medium CVE-2026-41066 severity moderate: SUSE including 7 source package names (python-lxml-doc-6.1.0-1.1, python311-lxml-6.1.0-1.1, …), 7 product×package rows across 1 product lines (openSUSE Tumbleweed): Fixed 7. https://www.suse.com/security/cve/CVE-2026-41066/
ubuntu medium CVE-2026-41066 medium priority: Ubuntu including 1 source packages (lxml), 9 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): needs-triage 6, needed 2, released 1. https://ubuntu.com/security/CVE-2026-41066

Affected software / configurations for CVE-2026-41066

Vendor Product Version Raw CPE
lxml lxml < 6.1.0 cpe:2.3:a:lxml:lxml:*:*:*:*:*:*:*:*

References for CVE-2026-41066

URL Tags
https://bugs.launchpad.net/lxml/+bug/2146291 Exploit Issue Tracking Third Party Advisory
https://github.com/lxml/lxml/security/advisories/GHSA-vfmq-68hx-4jfw Mitigation Vendor Advisory
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