Published: 21/03/2021 Updated: 07/11/2023

CVSS v2 Base Score: 4.3 | Impact Score: 2.9 | Exploitability Score: 8.6

CVSS v3 Base Score: 6.1 | Impact Score: 2.7 | Exploitability Score: 2.8

VMScore: 383

Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N

An XSS vulnerability exists in python-lxml's clean module versions prior to 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.

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debian debian linux 9.0
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fedoraproject fedora 33
fedoraproject fedora 34
netapp snapcenter -
oracle zfs storage appliance kit 8.8

Debian Bug report logs - #985643 lxml: CVE-2021-28957 Package: src:lxml; Maintainer for src:lxml is Matthias Klose <doko@debianorg>; Reported by: Salvatore Bonaccorso <carnil@debianorg> Date: Sun, 21 Mar 2021 09:24:01 UTC Severity: important Tags: security, upstream Found in version lxml/462-1 Forwarded to ht ...

Kevin Chung discovered that lxml, a Python binding for the libxml2 and libxslt libraries, did not properly sanitize its input This would allow a malicious user to mount a cross-site scripting attack For the stable distribution (buster), this problem has been fixed in version 432-1+deb10u3 We recommend that you upgrade your lxml packages For t ...

A flaw was found in python-lxml The HTML5 formaction attribute is not input sanitized like the HTML action attribute is which can lead to a Cross-Site Scripting attack (XSS) when an application uses python-lxml to sanitize user inputs The highest threat from this vulnerability is to data confidentiality and integrity as well as system availabilit ...

python-lxml 462 places the HTML action attribute into defslink_attrs (in html/defspy) for later use in input sanitization, but does not do the same for the HTML5 formaction attribute ...

CWE-79 https://bugs.launchpad.net/lxml/+bug/1888153 https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270 https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999 https://www.debian.org/security/2021/dsa-4880 https://security.netapp.com/advisory/ntap-20210521-0004/https://www.oracle.com/security-alerts/cpuoct2021.html https://security.gentoo.org/glsa/202208-06 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=985643 https://nvd.nist.gov https://www.debian.org/security/2021/dsa-4880

CVE-2021-28957

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