All vulnerabilities

Servers and applications

CVE-2021-3733

There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application…

Severity
Medium 6.5
Published
10 Mar 2022
Last changed
14 Oct 2026
Added to UpHeron
21 Oct 2026
Fixed in
3.6.14, 3.7.11, 3.8.10, 3.9.5
Sources
NVD

Affected software

SoftwareAffected versions
PythonServers and applications · cpe:a:python:python
  • Every version before 3.6.14
  • From 3.7.0 before 3.7.11
  • From 3.8.0 before 3.8.10
  • From 3.9.0 before 3.9.5
  • Version 3.10.0

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2021-3733
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2021-3733