Summary
Nokogiri < v1.13.4 contains an inefficient regular expression that is susceptible to excessive backtracking when attempting to detect encoding in HTML documents.
Mitigation
Upgrade to Nokogiri >= 1.13.4.
Severity
The Nokogiri maintainers have evaluated this as High Severity 7.5 (CVSS3.1).
References
CWE-1333 Inefficient Regular Expression Complexity
Credit
This vulnerability was reported by HackerOne user oooooooq (ななおく).
An XML eXternal Entity (XXE) flaw was found in Nokogiri, a Ruby gem for parsing HTML, XML, and SAX. Using external XML entities, a remote attacker could specify a URL in a specially crafted XML that, when parsed, would cause a connection to that URL to be opened.
A patch shipped with the 1.5.4 release of Nokogiri provided a "nonet" option to disable external connections. However, local file URLs could still be used to exploit this flaw. The 1.6.4 release of Nokogiri fixed this issue by using libxml2 2.9.0.
Additional information is detailed at:
https://github.com/sparklemotion/nokogiri/issues/693#issuecomment-68334768
CVE request and assignment:
http://seclists.org/oss-sec/2015/q1/57
Summary
The fork of org.cyberneko.html used by Nokogiri (Rubygem) raises a java.lang.OutOfMemoryError exception when parsing ill-formed HTML markup.
Severity
The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).
Mitigation
Upgrade to >= 1.9.22.noko2.
Credit
This vulnerability was reported by 이형관 (windshock).
References
CWE-400 Uncontrolled Resource Consumption
Notes
The upstream library org.cyberneko.html is no longer maintained. Nokogiri uses its own fork of this library located at https://github.com/sparklemotion/nekohtml and this CVE applies only to that fork. Other forks of nekohtml may have a similar vulnerability.
Nokogiri is an open source XML and HTML library for the Ruby programming language. Nokogiri 1.13.8 and 1.13.9 fail to check the return value from xmlTextReaderExpand in the method Nokogiri::XML::Reader#attributehash. This can lead to a null pointer exception when invalid markup is being parsed. For applications using XML::Reader to parse untrusted inputs, this may potentially be a vector for a denial of service attack. Users are advised to upgrade to Nokogiri >= 1.13.10. Users may be able to search their code for calls to either XML::Reader#attributes or XML::Reader#attributehash to determine if they are affected.
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, calling Document#encoding= with an invalid encoding (e.g., a non-string, or a string containing a null byte) raises an exception, but only after freeing the document's current encoding string without replacing it. The document is left referencing freed memory, so the next call to Document#encoding reads invalid memory, which can cause a segfault or leak freed bytes into a Ruby String. Affects the CRuby (libxml2) implementation only; JRuby is not affected. This vulnerability is fixed in 1.19.4.
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, calling Document#encoding= with an invalid encoding (e.g., a non-string, or a string containing a null byte) raises an exception, but only after freeing the document's current encoding string without replacing it. The document is left referencing freed memory, so the next call to Document#encoding reads invalid memory, which can cause a segfault or leak freed bytes into a Ruby String. Affects the CRuby (libxml2) implementation only; JRuby is not affected. This vulnerability is fixed in 1.19.4.