CVE-2020-5227

Feedgen (python feedgen) before 0.9.0 is susceptible to XML Denial of Service attacks. The *feedgen* library allows supplying XML as content for some of the available fields. This XML will be parsed and integrated into the existing XML tree. During this process, feedgen is vulnerable to XML Denial of Service Attacks (e.g. XML Bomb). This becomes a concern in particular if feedgen is used to include content from untrused sources and if XML (including XHTML) is directly included instead of providing plain tex content only. This problem has been fixed in feedgen 0.9.0 which disallows XML entity expansion and external resources.

Feedgen (python feedgen) before 0.9.0 is susceptible to XML Denial of Service attacks. The *feedgen* library allows supplying XML as content for some of the available fields. This XML will be parsed and integrated into the existing XML tree. During this process, feedgen is vulnerable to XML Denial of Service Attacks (e.g. XML Bomb). This becomes a concern in particular if feedgen is used to include content from untrused sources and if XML (including XHTML) is directly included instead of providing plain tex content only. This problem has been fixed in feedgen 0.9.0 which disallows XML entity expansion and external resources.

Feedgen (python feedgen) before 0.9.0 is susceptible to XML Denial of Service attacks. The *feedgen* library allows supplying XML as content for some of the available fields. This XML will be parsed and integrated into the existing XML tree. During this process, feedgen is vulnerable to XML Denial of Service Attacks (e.g. XML Bomb). This becomes a concern in particular if feedgen is used to include content from untrused sources and if XML (including XHTML) is directly included instead of providing plain tex content only. This problem has been fixed in feedgen 0.9.0 which disallows XML entity expansion and external resources.

### Impact The *feedgen* library allows supplying XML as content for some of the available fields. This XML will be parsed and integrated into the existing XML tree. During this process, feedgen is vulnerable to [XML Denial of Service Attacks](https://docs.microsoft.com/en-us/archive/msdn-magazine/2009/november/xml-denial-of-service-attacks-and-defenses) (e.g. XML Bomb). This becomes a concern in particular if feedgen is used to include content from untrused sources and if XML (including XHTML) is directly included instead of providing plain tex content only. ### Patches This problem has been fixed in feedgen 0.9.0 which disallows XML entity expansion and external resources. ### Workarounds Updating is strongly recommended and should not be problematic. Nevertheless, as a workaround, avoid providing XML directly to feedgen or ensure that no entity expansion is part of the XML. ### References - [Security Briefs - XML Denial of Service Attacks and Defenses](https://docs.microsoft.com/en-us/archive/msdn-magazine/2009/november/xml-denial-of-service-attacks-and-defenses) - [Billion laughs attack](https://en.wikipedia.org/wiki/Billion_laughs_attack#cite_note-2) ### For more information If you have any questions or comments about this advisory: - Open an issue in [lkiesow/python-feedgen](https://github.com/lkiesow/python-feedgen/issues) - Send an email to security@lkiesow.de

Feedgen (python feedgen) versiones anteriores a 0.9.0, es susceptible a ataques de Denegación de Servicio XML. La biblioteca *feedgen* permite suministrar XML como contenido para algunos de los campos disponibles. Este XML será analizado e integrado en el árbol XML existente. Durante este proceso, feedgen es vulnerable a Ataques de Denegación de Servicio XML (por ejemplo, XML Bomb). Esto se convierte en una preocupación en particular si feedgen es usado para incluir contenido desde fuentes no confiables y si XML (incluido XHTML) es incluido directamente en lugar de proporcionar solo contenido de texto plano. Este problema ha sido corregido en feedgen versión 0.9.0 que no permite la expansión de entidades XML y recursos externos.