# CVE-2011-1156: feedparser denial of service vulnerability

Source: https://junglewise.ai/threats/cve-2011-1156-feedparser-denial-of-service-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2011-04-11  
License: CC BY 4.0 with a link back

CVE-2011-1156 · Severity: low · CVSS 3.1 · Published 2011-04-11

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.

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

## Quick answers

**Is CVE-2011-1156 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2011-1156 being exploited in the wild.

**How severe is CVE-2011-1156?** 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=5.0.1, ECOSYSTEM:introduced=4.1,fixed=5.0.1.

**Is there a fix for CVE-2011-1156?** Yes. feedparser (PyPI): upgrade to 5.0.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2011-1156?** 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 5.0.1 or later

  ```sh
  pip install "feedparser>=5.0.1"
  ```


## Affected products

- feedparser (PyPI) ECOSYSTEM:introduced=0,fixed=5.0.1, ECOSYSTEM:introduced=4.1,fixed=5.0.1

## Identifiers

- CVE-2011-1156
- GHSA-6h52-4vmh-8x4f
- PYSEC-2011-19

## 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 Cross-site Scripting vulnerability](https://junglewise.ai/threats/cve-2011-1158-feedparser-cross-site-scripting-vulnerability)
- [feedparser cross-site scripting in nested CDATA parsing](https://junglewise.ai/threats/cve-2009-5065-feedparser-cross-site-scripting-in-nested-cdata-parsing)