Vulnerability Intelligence Report
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 availability.
No Active Exploit Signals
CVSS Base Score
6.5
MEDIUM
EPSS Probability:4.67%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-400 ↗CWE-400 - Uncontrolled Resource Consumption
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| python | python | 3.10.0 |
| redhat | codeready_linux_builder | 8.0 |
| redhat | codeready_linux_builder_for_ibm_z_systems | 8.0 |
| redhat | codeready_linux_builder_for_power_little_endian | 8.0 |
| redhat | enterprise_linux | 8.0 |
| redhat | enterprise_linux_eus | 8.4 |
| redhat | enterprise_linux_for_ibm_z_systems | 8.0 |
| redhat | enterprise_linux_for_ibm_z_systems_eus | 8.4 |
| redhat | enterprise_linux_for_power_little_endian | 8.0 |
| redhat | enterprise_linux_for_power_little_endian_eus | 8.4 |
| redhat | enterprise_linux_server_aus | 8.4 |
| redhat | enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions | 8.4 |
| redhat | enterprise_linux_server_tus | 8.4 |
| redhat | enterprise_linux_server_update_services_for_sap_solutions | 8.4 |
| fedoraproject | extra_packages_for_enterprise_linux | 7.0 |
| fedoraproject | fedora | 33, 34, 35, 36 |
| netapp | management_services_for_element_software_and_netapp_hci | all |
| netapp | ontap_select_deploy_administration_utility | all |
| netapp | solidfire\,_enterprise_sds_\&_hci_storage_node | all |
| netapp | hci_compute_node_firmware | all |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
4.675%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Red Hat, Inc. · Vendor · USA |
| Reserved | 2021-08-23T00:00:00 |
| Published | 2022-03-07T00:00:00 |
| Last Updated | 2025-11-03T21:45:06 |
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