GitHub Advisoryadvisory · PyPI
GHSA-g8q7-xv52-hf9f Feedgen Vulnerable to XML Denial of Service Attacks
MEDIUM
Official page ↗
- Aliases
- CVE-2020-5227
- Ecosystem
- PyPI
- Packages
- feedgen
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-776
- Reviewed
- 2020-01-28
Affected packages
• PyPI feedgen: < 0.9.0 → fixed in 0.9.0
Description
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 (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
• Billion laughs attack
For more information
If you have any questions or comments about this advisory:
• Open an issue in lkiesow/python-feedgen
• Send an email to [email protected]
Related
Alias · CVE (1)
- CVE-2020-5227 Feedgen (python feedgen) before 0.9.0 is susceptible to XML Denial of Service attacks. vulnerability
Weakness · CWE (1)
- CWE-776 Improper Restriction of Recursive Entity References in DTDs weakness
References
- https://github.com/lkiesow/python-feedgen/security/advisories/GHSA-g8q7-xv52-hf9f web
- https://nvd.nist.gov/vuln/detail/CVE-2020-5227 advisory
- https://github.com/lkiesow/python-feedgen/commit/f57a01b20fa4aaaeccfa417f28e66b4084b9d0cf web
- https://docs.microsoft.com/en-us/archive/msdn-magazine/2009/november/xml-denial-of-service-attacks-and-defenses web
- https://github.com/lkiesow/python-feedgen package
- https://github.com/pypa/advisory-database/tree/main/vulns/feedgen/PYSEC-2020-231.yaml web
- https://lists.fedoraproject.org/archives/list/[email protected]/message/T6I5ENUYGFNMIH6ZQ62FZ6VU2WD3SIOI web