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lkiesow/python-feedgen · Security

Feedgen Vulnerable to XML Denial of Service Attacks

GHSA ID
GHSA-g8q7-xv52-hf9f
CVE ID
CVE-2020-5227
Severity
medium
Published
Updated
CVSS
4.4 · CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
CVSS v3
4.4 · CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
CVSS v4
5.9 · CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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

For more information

If you have any questions or comments about this advisory:

CWEs

  • CWE-776 · Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')

References