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                            CERT-Renater

                 Note d'Information No. 2021/VULN109
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DATE                : 07/03/2022

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S) : Systems running Nokogiri versions prior to 1.13.2.

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https://github.com/advisories/GHSA-fq42-c5rg-92c2
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Vulnerable dependencies in Nokogiri
High severity GitHub Reviewed

Vulnerability details

Package
nokogiri (RubyGems)

Affected versions
< 1.13.2

Patched versions
1.13.2

Description

Summary
Nokogiri v1.13.2 upgrades two of its packaged dependencies:

vendored libxml2 from v2.9.12 to v2.9.13
vendored libxslt from v1.1.34 to v1.1.35
Those library versions address the following upstream CVEs:

libxslt: CVE-2021-30560 (CVSS 8.8, High severity)
libxml2: CVE-2022-23308 (Unspecified severity, see more information
below)
Those library versions also address numerous other issues including
performance improvements, regression fixes, and bug fixes, as well as
memory leaks and other use-after-free issues that were not assigned CVEs.

Please note that this advisory only applies to the CRuby implementation
of Nokogiri < 1.13.2, and only if the packaged libraries are being used.
If you've overridden defaults at installation time to use system
libraries instead of packaged libraries, you should instead pay
attention to your distro's libxml2 and libxslt release announcements.


Mitigation
Upgrade to Nokogiri >= 1.13.2.

Users who are unable to upgrade Nokogiri may also choose a more complicated
mitigation: compile and link an older version Nokogiri against external
libraries libxml2 >= 2.9.13 and libxslt >= 1.1.35, which will also address
these same CVEs.


Impact

libxslt CVE-2021-30560
CVSS3 score: 8.8 (High)

Fixed by https://gitlab.gnome.org/GNOME/libxslt/-/commit/50f9c9c
All versions of libxslt prior to v1.1.35 are affected.

Applications using untrusted XSL stylesheets to transform XML
are vulnerable to a denial-of-service attack and should be
upgraded immediately.


libxml2 CVE-2022-23308
As of the time this security advisory was published, there is
no officially published information available about this CVE's
severity. The above NIST link does not yet have a published record,
and the libxml2 maintainer has declined to provide a severity score.

Fixed by https://gitlab.gnome.org/GNOME/libxml2/-/commit/652dd12

Further explanation is at
https://mail.gnome.org/archives/xml/2022-February/msg00015.html
The upstream commit and the explanation linked above indicate that
an application may be vulnerable to a denial of service, memory
disclosure, or code execution if it parses an untrusted document
with parse options DTDVALID set to true, and NOENT set to false.

An analysis of these parse options:

While NOENT is off by default for Document, DocumentFragment, Reader,
and Schema parsing, it is on by default for XSLT (stylesheet) parsing
in Nokogiri v1.12.0 and later.
DTDVALID is an option that Nokogiri does not set for any operations,
and so this CVE applies only to applications setting this option
explicitly.

It seems reasonable to assume that any application explicitly setting
the parse option DTDVALID when parsing untrusted documents is vulnerable
and should be upgraded immediately.


References

GHSA-fq42-c5rg-92c2
@flavorjones flavorjones published the maintainer security advisory

CVE ID
No known CVE

GHSA ID
GHSA-fq42-c5rg-92c2

CWEs
CWE-416



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