CVE-2021-3733

Signals

NVD · CVE-2026-64604 · In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Grab vmcs12 on CR8 interception update iff vCPU is in guest mode When updating CR8NVD · CVE-2026-64603 · In the Linux kernel, the following vulnerability has been resolved: platform/x86: intel-hid: Protect ACPI notify handler against recursion Since commit e2ffcda1NVD · CVE-2026-64602 · In the Linux kernel, the following vulnerability has been resolved: iio: adc: spear: Initialize completion before requesting IRQ In the report from Jaeyoung ChuNVD · CVE-2026-64601 · In the Linux kernel, the following vulnerability has been resolved: ALSA: us144mkii: capture_urb_complete: redundant usb_anchor_urb corrupts anchor list on eachCISA KEV · CVE-2026-63077 · 9.8 · JetBrains TeamCity Deserialization of Untrusted Data Vulnerability · Added 2026-08-05 · Due 2026-08-08CISA KEV · CVE-2026-18556 · 7.4 · N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability · Added 2026-08-04 · Due 2026-08-07NVD · CVE-2026-64604 · In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Grab vmcs12 on CR8 interception update iff vCPU is in guest mode When updating CR8NVD · CVE-2026-64603 · In the Linux kernel, the following vulnerability has been resolved: platform/x86: intel-hid: Protect ACPI notify handler against recursion Since commit e2ffcda1NVD · CVE-2026-64602 · In the Linux kernel, the following vulnerability has been resolved: iio: adc: spear: Initialize completion before requesting IRQ In the report from Jaeyoung ChuNVD · CVE-2026-64601 · In the Linux kernel, the following vulnerability has been resolved: ALSA: us144mkii: capture_urb_complete: redundant usb_anchor_urb corrupts anchor list on eachCISA KEV · CVE-2026-63077 · 9.8 · JetBrains TeamCity Deserialization of Untrusted Data Vulnerability · Added 2026-08-05 · Due 2026-08-08CISA KEV · CVE-2026-18556 · 7.4 · N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability · Added 2026-08-04 · Due 2026-08-07

CVE Database · CVE-2021-3733

CVE-2021-3733

· MEDIUMModified

CVSS v3.1

6.5

EPSS

4.67%

Published

Mar 10, 2022

Modified

Nov 3, 2025

Public PoC / Exploit (1)

All weaponized →

TrickestTrickest PoC index

Links to public security research (Exploit-DB, Nuclei, Trickest, GitHub) for defensive use only.

Description

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

CWE-400CWE-400

Affected Products (27)

python · python (up to 3.6.14)vulnerable

python · python (up to 3.7.11)vulnerable

python · python (up to 3.8.10)vulnerable

python · python (up to 3.9.5)vulnerable

python · pythonvulnerable

redhat · codeready_linux_buildervulnerable

redhat · codeready_linux_builder_for_ibm_z_systemsvulnerable