Loofah allows non-whitelisted attributes to be present in sanitized output when input with specially-crafted HTML fragments.

Users are affected if running Loofah < 2.2.1, but only:

• when running on MRI or RBX,
• in combination with libxml2 >= 2.9.2.

JRuby users are not affected.

References

• https://nvd.nist.gov/vuln/detail/CVE-2018-8048
• flavorjones/loofah#144
• GHSA-x7rv-cr6v-4vm4
• https://security.netapp.com/advisory/ntap-20191122-0003/
• https://www.debian.org/security/2018/dsa-4171
• http://www.openwall.com/lists/oss-security/2018/03/19/5
• flavorjones/loofah@f739cf8
• sparklemotion/nokogiri#1746
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/CVE-2018-8048.yml
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/nokogiri/CVE-2018-8048.yml