CVE-2021-23336

5.9 MEDIUM
Published: February 15, 2021 Modified: December 17, 2025

Description

The package python/cpython from 0 and before 3.6.13, from 3.7.0 and before 3.7.10, from 3.8.0 and before 3.8.8, from 3.9.0 and before 3.9.2 are 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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/02/19/4
Source: report@snyk.io
Mailing List Patch Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/01/2
Source: report@snyk.io
Mailing List Third Party Advisory
https://github.com/python/cpython/pull/24297
Source: report@snyk.io
Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00030.html
Source: report@snyk.io
Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00005.html
Source: report@snyk.io
Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00015.html
Source: report@snyk.io
Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202104-04
Source: report@snyk.io
Third Party Advisory
https://security.netapp.com/advisory/ntap-20210326-0004/
Source: report@snyk.io
Third Party Advisory
https://snyk.io/blog/cache-poisoning-in-popular-open-source-packages/
Source: report@snyk.io
Technical Description Third Party Advisory
https://snyk.io/vuln/SNYK-UPSTREAM-PYTHONCPYTHON-1074933
Source: report@snyk.io
Exploit Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html
Source: report@snyk.io
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuApr2021.html
Source: report@snyk.io
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html
Source: report@snyk.io
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html
Source: report@snyk.io
Patch Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/02/19/4
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Patch Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/05/01/2
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://github.com/python/cpython/pull/24297
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00030.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00005.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00015.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202104-04
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://security.netapp.com/advisory/ntap-20210326-0004/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://snyk.io/blog/cache-poisoning-in-popular-open-source-packages/
Source: af854a3a-2127-422b-91ae-364da2661108
Technical Description Third Party Advisory
https://snyk.io/vuln/SNYK-UPSTREAM-PYTHONCPYTHON-1074933
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuApr2021.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory

74 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.9 / 10.0
EPSS (Exploit Probability)
0.3%
51th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

debian djangoproject python fedoraproject oracle netapp