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GLSA-202208-06 : lxml: Multiple Vulnerabilities
high Nessus Plugin ID 163984
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Description
The remote host is affected by the vulnerability described in GLSA-202208-06 (lxml: Multiple Vulnerabilities)- An XSS vulnerability was discovered in python-lxml's clean module versions before 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.
(CVE-2021-28957)
- 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. (CVE-2021-43818)
- NULL Pointer Dereference allows attackers to cause a denial of service (or application crash). This only applies when lxml is used together with libxml2 2.9.10 through 2.9.14. libxml2 2.9.9 and earlier are not affected. It allows triggering crashes through forged input data, given a vulnerable code sequence in the application. The vulnerability is caused by the iterwalk function (also used by the canonicalize function). Such code shouldn't be in wide-spread use, given that parsing + iterwalk would usually be replaced with the more efficient iterparse function. However, an XML converter that serialises to C14N would also be vulnerable, for example, and there are legitimate use cases for this code sequence. If untrusted input is received (also remotely) and processed via iterwalk function, a crash can be triggered.
(CVE-2022-2309)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
All lxml users should upgrade to the latest version:# emerge --sync # emerge --ask --oneshot --verbose >=dev-python/lxml-4.9.1
See Also
https://security.gentoo.org/glsa/202208-06
https://bugs.gentoo.org/show_bug.cgi?id=777579
Plugin Details
Severity: High
ID: 163984
File Name: gentoo_GLSA-202208-06.nasl
Version: 1.3
Type: local
Family: Gentoo Local Security Checks
Published: 8/10/2022
Updated: 10/16/2023
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 4.4
CVSS v2
Risk Factor: Medium
Base Score: 6.8
Temporal Score: 5.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P
CVSS Score Source: CVE-2021-43818
CVSS v3
Risk Factor: High
Base Score: 7.1
Temporal Score: 6.4
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C
Vulnerability Information
CPE: p-cpe:/a:gentoo:linux:lxml, cpe:/o:gentoo:linux
Required KB Items: Host/local_checks_enabled, Host/Gentoo/release, Host/Gentoo/qpkg-list
Exploit Available: true
Exploit Ease: Exploits are available
Patch Publication Date: 8/10/2022
Vulnerability Publication Date: 3/21/2021