# CVE-2009-5065: feedparser cross-site scripting in nested CDATA parsing

Source: https://junglewise.ai/threats/cve-2009-5065-feedparser-cross-site-scripting-in-nested-cdata-parsing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2011-04-11. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2009-5065 · Severity: low · CVSS 3.1 · Published 2011-04-11

feedparser is a widely-used Python library that parses RSS and Atom feeds from online sources. A cross-site scripting (XSS) vulnerability in the library allows attackers to inject malicious scripts into feed content by exploiting improper handling of nested CDATA sections. When a victim views a maliciously crafted feed, the injected code executes in their browser, potentially compromising account credentials, stealing session data, or performing unauthorized actions on their behalf.

Technologies: [feedparser (PyPI)](https://junglewise.ai/threats/technologies/feedparser). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2009-5065 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2009-5065 being exploited in the wild.

**How severe is CVE-2009-5065?** Low severity, with a CVSS score of 3.1, published 11 April 2011.

**Which products and versions are affected?** feedparser (PyPI) ECOSYSTEM:introduced=0,fixed=5.0.

**Is there a fix for CVE-2009-5065?** Yes. feedparser (PyPI): upgrade to 5.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2009-5065 attacked?** It is attacked over the network.

**Am I affected by CVE-2009-5065?** Check whether you run feedparser (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- feedparser (PyPI): upgrade to 5.0 or later

  ```sh
  pip install "feedparser>=5.0"
  ```


## Technical details

The vulnerability is a reflected cross-site scripting (XSS) flaw in feedparser.py that stems from insufficient sanitization of nested CDATA stanzas. An attacker can craft a malicious RSS or Atom feed containing specially formatted nested CDATA sections that cause the parser to emit unescaped HTML or JavaScript. The attack requires the victim to parse and view the malicious feed content, typically via an application that uses feedparser as a backend. No authentication is required, and the vulnerability affects all versions prior to 5.0. The issue has been patched in feedparser 5.0 and later.

## Affected products

- Python Feedparser Developers feedparser < 5.0

## Identifiers

- CVE-2009-5065
- GHSA-3mwg-gp5g-fv3q
- PYSEC-2011-18

## Timeline

- 2011-04-11: disclosed: CVE-2009-5065 published
- 2011: patched: Fixed in version 5.0

## References

- [https://bugzilla.novell.com/show_bug.cgi?id=680074](https://bugzilla.novell.com/show_bug.cgi?id=680074)

## Related threats

- [feedparser denial of service vulnerability](https://junglewise.ai/threats/cve-2012-2921-feedparser-denial-of-service-vulnerability)
- [feedparser Cross-site Scripting in XML comment parsing](https://junglewise.ai/threats/cve-2011-1157-feedparser-cross-site-scripting-in-xml-comment-parsing)
- [feedparser denial of service vulnerability](https://junglewise.ai/threats/cve-2011-1156-feedparser-denial-of-service-vulnerability)
- [feedparser Cross-site Scripting vulnerability](https://junglewise.ai/threats/cve-2011-1158-feedparser-cross-site-scripting-vulnerability)