CVE-2021-21240

httplib2 is a comprehensive HTTP client library for Python. In httplib2 before version 0.19.0, a malicious server which responds with long series of "\xa0" characters in the "www-authenticate" header may cause Denial of Service (CPU burn while parsing header) of the httplib2 client accessing said server. This is fixed in version 0.19.0 which contains a new implementation of auth headers parsing using the pyparsing library.

• CWE-400

• https://github.com/httplib2/httplib2/commit/bd9ee252c8f099608019709e22c0d705e98d26bcPatch, Third Party Advisory
• https://github.com/httplib2/httplib2/pull/182Patch, Third Party Advisory
• https://github.com/httplib2/httplib2/security/advisories/GHSA-93xj-8mrv-444mExploit, Mitigation, Third Party Advisory
• https://pypi.org/project/httplib2Product, Third Party Advisory
• https://github.com/httplib2/httplib2/commit/bd9ee252c8f099608019709e22c0d705e98d26bcPatch, Third Party Advisory
• https://github.com/httplib2/httplib2/pull/182Patch, Third Party Advisory
• https://github.com/httplib2/httplib2/security/advisories/GHSA-93xj-8mrv-444mExploit, Mitigation, Third Party Advisory
• https://pypi.org/project/httplib2Product, Third Party Advisory

Published

Feb 8, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2021-21235kamadak-exif is an exif parsing library written in pure Rust…6.5
• CVE-2021-21236CairoSVG is a Python (pypi) package. CairoSVG is an SVG conv…5.5
• CVE-2021-21237Git LFS is a command line extension for managing large files…7.8
• CVE-2021-21238PySAML2 is a pure python implementation of SAML Version 2 St…6.5
• CVE-2021-21239PySAML2 is a pure python implementation of SAML Version 2 St…6.5
• CVE-2021-2124Vulnerability in the Oracle VM VirtualBox product of Oracle …6
• CVE-2021-21241The Python "Flask-Security-Too" package is used for adding s…7.4
• CVE-2021-21242OneDev is an all-in-one devops platform. In OneDev before ve…9.8
• CVE-2021-21243OneDev is an all-in-one devops platform. In OneDev before ve…9.8
• CVE-2021-21244OneDev is an all-in-one devops platform. In OneDev before ve…9.8
• CVE-2021-21245OneDev is an all-in-one devops platform. In OneDev before ve…9.8
• CVE-2021-21246OneDev is an all-in-one devops platform. In OneDev before ve…7.5