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:
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
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.
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.
Summary
Nokogiri v1.13.2 upgrades two of its packaged dependencies:
Those library versions address the following upstream CVEs:
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'slibxml2andlibxsltrelease 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
>= 2.9.13and libxslt>= 1.1.35, which will also address these same CVEs.Impact
libxslt CVE-2021-30560
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
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
DTDVALIDset to true, andNOENTset to false.An analysis of these parse options:
NOENTis 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.DTDVALIDis 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
DTDVALIDwhen parsing untrusted documents is vulnerable and should be upgraded immediately.