{"cve":"CVE-2021-23336","nvd":{"published":"2021-02-15T13:15:12.433","modified":"2026-10-14T12:17:09.467","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H","score":5.9},"cwes":["CWE-444"],"references":["http://www.openwall.com/lists/oss-security/2021/02/19/4","http://www.openwall.com/lists/oss-security/2021/05/01/2","https://github.com/python/cpython/pull/24297","https://lists.apache.org/thread.html/ra8ce70088ba291f358e077cafdb14d174b7a1ce9a9d86d1b332d6367%40%3Cusers.airflow.apache.org%3E","https://lists.apache.org/thread.html/rc005f4de9d9b0ba943ceb8ff5a21a5c6ff8a9df52632476698d99432%40%3Cannounce.apache.org%3E"],"products":["debian:debian_linux","djangoproject:django","fedoraproject:fedora","netapp:cloud_backup","netapp:inventory_collect_tool","netapp:ontap_select_deploy_administration_utility","netapp:snapcenter","oracle:communications_offline_mediation_controller","oracle:communications_pricing_design_center","oracle:enterprise_manager_ops_center","oracle:zfs_storage_appliance","python:python"],"source":"nvd","synced_at":"2026-10-19T21:15:50.279857260+00:00"},"epss":{"cve":"CVE-2021-23336","score":0.40736,"percentile":0.98643,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}