Multiple vulnerabilities has been found and corrected in
python-feedparser:

Cross-site scripting (XSS) vulnerability in feedparser.py in Universal
Feed Parser (aka feedparser or python-feedparser) before 5.0 allows
remote attackers to inject arbitrary web script or HTML via vectors
involving nested CDATA stanzas (CVE-2009-5065).

feedparser.py in Universal Feed Parser (aka feedparser or
python-feedparser) before 5.0.1 allows remote attackers to cause
a denial of service (application crash) via a malformed DOCTYPE
declaration (CVE-2011-1156).

Cross-site scripting (XSS) vulnerability in feedparser.py in Universal
Feed Parser (aka feedparser or python-feedparser) 5.x before 5.0.1
allows remote attackers to inject arbitrary web script or HTML via
malformed XML comments (CVE-2011-1157).

Cross-site scripting (XSS) vulnerability in feedparser.py in Universal
Feed Parser (aka feedparser or python-feedparser) 5.x before 5.0.1
allows remote attackers to inject arbitrary web script or HTML
via an unexpected URI scheme, as demonstrated by a javascript: URI
(CVE-2011-1158).

The updated packages have been patched to correct these issues.