CVE-2021-3733
MEDIUM severity · CVSS 6.5 · Uncontrolled resource consumption
6.5CVSS MEDIUM
Summary
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 availability.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
Confidentiality impactNone
Integrity impactNone
Availability impactHigh
Exploit probability (EPSS)1%
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products we track (2)
Recommendation
Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.
Official patch: https://bugs.python.org/issue43075 ↗
Additional information
- NVD record
- https://bugs.python.org/issue43075Patch
- https://github.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fbPatch
- https://github.com/python/cpython/pull/24391Patch
- https://ubuntu.com/security/CVE-2021-3733Patch
- https://bugzilla.redhat.com/show_bug.cgi?id=1995234Advisory
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html
- https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html
- https://security.netapp.com/advisory/ntap-20220407-0001/Advisory