CVE-2021-23336
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Insights vulnerability analysis
Description
The package python/cpython is vulnerable to Web Cache Poisoning via urllib.parse.parse_qsl and urllib.parse.parse_qs by using a vector called parameter cloaking. When the attacker can separate query parameters using a semicolon (;), they can cause a difference in the interpretation of the request between the proxy (running with default configuration) and the server. This can result in malicious requests being cached as completely safe ones, as the proxy would usually not see the semicolon as a separator, and therefore would not include it in a cache key of an unkeyed parameter.
Statement
The python36 component in the python36:3.6 module in Red Hat Enterprise Linux 8 is listed as not affected, as it does not contain Python interpreter or libraries. Packages of the python36 component only provide convenient links to the Python interpreter included in the non-modular python3 component's platform-python packages. Users of python36:3.6 module also need to check the entry for the python3 component to determine if their systems are affected.
Red Hat Ceph Storage (RHCS) 3 ships an older version of python-django without the directly affected function, but which is still vulnerable to a similar attack involving the semi colon separator. Hence, impact has been rated as Low.
Although Red Hat OpenStack Platform 13 & 16.1 both ship the affected code, since the proxy is controlled and configured by OpenStack, the impact has been lowered to Low. As a fix would require a substantial effort or commitment of time, no fix will be provided at this time.
Additional information
- Bugzilla 1928904: python: Web cache poisoning via urllib.parse.parse_qsl and urllib.parse.parse_qs by using a semicolon in query parameters
- CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
- FAQ: Frequently asked questions about CVE-2021-23336
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
Red Hat | NVD | |
---|---|---|
CVSS v3 Base Score | 5.9 | 5.9 |
Attack Vector | Network | Network |
Attack Complexity | High | High |
Privileges Required | None | None |
User Interaction | Required | Required |
Scope | Unchanged | Unchanged |
Confidentiality Impact | None | None |
Integrity Impact | Low | Low |
Availability Impact | High | High |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
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My product is listed as "Out of Support Scope". What does this mean?
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