An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Urllib3 | Python | 1.25.4 (including) | 1.26.5 (excluding) |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | automation-hub-0:4.2.6-1.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python3-chardet-0:3.0.4-3.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python3-click-0:7.1.2-3.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python3-gnupg-0:0.4.6-3.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python3-jinja2-0:2.11.2-3.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python3-markupsafe-0:1.1.1-4.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python3-semantic-version-0:2.8.5-3.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python-galaxy-ng-0:4.2.6-1.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 7 | RedHat | python-urllib3-0:1.26.5-1.el7pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | automation-hub-0:4.2.6-1.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python3-click-0:7.1.2-3.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python3-gnupg-0:0.4.6-3.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python3-jinja2-0:2.11.2-3.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python3-markupsafe-0:1.1.1-4.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python3-semantic-version-0:2.8.5-3.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python-galaxy-ng-0:4.2.6-1.el8pc | * |
| Red Hat Automation Hub 4.2 for RHEL 8 | RedHat | python-urllib3-0:1.26.5-1.el8pc | * |
| Red Hat Enterprise Linux 8 | RedHat | python39:3.9-8050020210811100211.d428a79b | * |
| Red Hat Enterprise Linux 8 | RedHat | python39-devel:3.9-8050020210811100211.d428a79b | * |
| Red Hat Enterprise Linux 8 | RedHat | python38:3.8-8050020210811101222.e3d35cca | * |
| Red Hat Enterprise Linux 8 | RedHat | python38-devel:3.8-8050020210811101222.e3d35cca | * |
| Red Hat Satellite 6.10 for RHEL 7 | RedHat | python-urllib3-0:1.26.5-1.el7pc | * |
| Red Hat Satellite 6.10 for RHEL 7 | RedHat | python-urllib3-0:1.26.5-1.el7pc | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-babel-0:2.7.0-12.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-python-0:3.8.11-2.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-python-cryptography-0:2.8-5.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-python-jinja2-0:2.10.3-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-python-lxml-0:4.4.1-7.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-python-pip-0:19.3.1-2.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | rh-python38-python-urllib3-0:1.25.7-7.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-babel-0:2.7.0-12.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-python-0:3.8.11-2.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-python-cryptography-0:2.8-5.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-python-jinja2-0:2.10.3-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-python-lxml-0:4.4.1-7.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-python-pip-0:19.3.1-2.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS | RedHat | rh-python38-python-urllib3-0:1.25.7-7.el7 | * |
| Python-pip | Ubuntu | esm-apps/focal | * |
| Python-pip | Ubuntu | focal | * |
| Python-pip | Ubuntu | groovy | * |
| Python-pip | Ubuntu | hirsute | * |
| Python-pip | Ubuntu | trusty | * |
| Python-pip | Ubuntu | upstream | * |
| Python-urllib3 | Ubuntu | esm-infra/focal | * |
| Python-urllib3 | Ubuntu | focal | * |
| Python-urllib3 | Ubuntu | groovy | * |
| Python-urllib3 | Ubuntu | hirsute | * |
| Python-urllib3 | Ubuntu | trusty | * |
| Python-urllib3 | Ubuntu | upstream | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.