CVE-2021-43818

mediumpriority · track · 29EPSS 0.027 · 86 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.66% (86th) EPSS

CVSS 6.8 · medium

Is it mine?

49 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.

cvss

Technical severity, 0–10. One row per scoring source.

8.2

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–8.2

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4

v3.17.1highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Lprimary · NVD / NIST USexploitability 2.8 · impact 3.7

v3.18.2highAV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:Nsecondary · FSTEC (BDU) RU

v3.18.2highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:Nsecondary · ENISA EU

v3.18.2highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:Nsecondary · security-advisories@github.comexploitability 2.8 · impact 4.7

v3.18.2highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:Nsecondary · OSV

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USprimaryCWE-74USCWE-74USCWE-77USCWE-79USCWE-79US

affected products (49)

Products and version ranges known to be affected.

Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
Xerox FreeFlow Print Server 7all versionscert_bundDEcpe:/a:xerox:freeflow_print_server:7
Xerox FreeFlow Print Server 9all versionscert_bundDEcpe:/a:xerox:freeflow_print_server:9
Xerox FreeFlow Print Server v9all versionscert_bundDEcpe:/a:xerox:freeflow_print_server:v9
lxml lxml≤ < 4.6.5enisa_euvdEU
Canonical Ltd. Ubuntu≤ 18.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 21.10fstec_bduRU
Canonical Ltd. Ubuntu≤ 16.04 ESMfstec_bduRU
Canonical Ltd. Ubuntu≤ 21.04fstec_bduRU
Canonical Ltd. Ubuntu≤ 20.04 LTSfstec_bduRU
Canonical Ltd. Ubuntu≤ 14.04 ESMfstec_bduRU
Fedora Project Fedora≤ 34fstec_bduRU
Fedora Project Fedora≤ 35fstec_bduRU
Red Hat Inc. Ansible Automation Platform≤ 2.0fstec_bduRU
Red Hat Inc. Ansible Automation Platform≤ 1.2fstec_bduRU
Red Hat Inc. Ansible Tower≤ 3fstec_bduRU
Red Hat Inc. Red Hat Enterprise Linux≤ 8fstec_bduRU
Red Hat Inc. Red Hat Satellite≤ 6.0fstec_bduRU
Red Hat Inc. Red Hat Software Collectionsall versionsfstec_bduRU
Red Hat Inc. Red Hat Update Infrastructure for Cloud Providers≤ 3fstec_bduRU

showing 20 of 49

advisories (6)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2022-0302Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen Ausführen von beliebigem Programmcode mit AdministratorrechtenDeutsch2022-06-14csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um beliebigen Programmcode auszuführen, einen Cross-Site-Scripting-Angriff durchzuführen, Informationen offenzulegen, einen Denial-of-Service-Zustand zu verursachen oder Dateien zu manipulieren.
WID-SEC-W-2022-0432Xerox FreeFlow Print Server: Mehrere SchwachstellenDeutsch2022-06-21csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um die Vertraulichkeit, Verfügbarkeit und Integrität zu gefährden.
WID-SEC-W-2022-0575Python: Schwachstelle ermöglicht CodeausführungDeutsch2022-05-01csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Python ausnutzen, um beliebigen Programmcode auszuführen.
WID-SEC-W-2024-1086IBM QRadar SIEM: Mehrere SchwachstellenDeutsch2024-05-09csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand herbeizuführen, vertrauliche Informationen offenzulegen, Dateien zu manipulieren, seine Privilegien zu erweitern, einen Cross-Site-Scripting (XSS)-Angriff durchzuführen oder einen nicht spezifizierten Angriff auszuführen.
GHSA-55x5-fj6c-h6m8lxml's HTML Cleaner allows crafted and SVG embedded scripts to pass through2021-12-13ghsa · osvUS
### Impact The HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5. ### Patches The issue has been resolved in lxml 4.6.5. ### Workarounds None. ### References The issues are tracked under the report IDs GHSL-2021-1037 and GHSL-2021-1038.
PYSEC-2021-8522021-12-13vendor · osvUS
lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.

also known as (7)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv cert_bund NVD CVE.org MITRE

published 2021-12-13modified 2026-06-17

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+53008 more

references (60)

External citations — patches, advisories, analysis.

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