CVE-2021-23336
Web Cache Poisoning
At a glance
- Severity
- MEDIUM 5.9
- EPSS
- EPSS 40.74 % · percentile 99 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- snyk
- NVD 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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H/E:P/RL:U/RC:C | snyk |
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H | NVD · report@snyk.io (Secondary) |
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 2.0 | MEDIUM 4.0 | AV:N/AC:H/Au:N/C:N/I:P/A:P | NVD · nvd@nist.gov (Primary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2021-10423
- GCVE · GCVE-0-2021-23336
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1378 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1094 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0933 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0395 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2023-AVI-1015 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
- CERTFR-2023-AVI-0513 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2022-AVI-525 — Multiples vulnérabilités dans les produits Fortinet · cert.ssi.gouv.fr
- CERTFR-2021-AVI-791 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2021-AVI-556 — Multiples vulnérabilités dans Oracle Database Server · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*< 3.6.13cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.7.0 < 3.7.10cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.8.0 < 3.8.8cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.9.0 < 3.9.2cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*cpe:2.3:a:netapp:inventory_collect_tool:-:*:*:*:*:*:*:*cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*cpe:2.3:a:netapp:snapcenter:-:*:*:*:*:*:*:*cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*≥ 2.2 < 2.2.19cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*≥ 3.0 < 3.0.13cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:*≥ 3.1 < 3.1.7cpe:2.3:a:oracle:communications_offline_mediation_controller:12.0.0.3.0:*:*:*:*:*:*:*cpe:2.3:a:oracle:communications_pricing_design_center:12.0.0.3.0:*:*:*:*:*:*:*cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:*cpe:2.3:o:oracle:zfs_storage_appliance:8.8:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| python/cpython | affected 0 < unspecified ; affected unspecified < 3.6.13 ; affected 3.7.0 < unspecified ; affected unspecified < 3.7.10 ; affected 3.8.0 < unspecified ; affected unspecified < 3.8.8 |
References
- https://snyk.io/vuln/SNYK-UPSTREAM-PYTHONCPYTHON-1074933
- https://github.com/python/cpython/pull/24297
- https://snyk.io/blog/cache-poisoning-in-popular-open-source-packages/
- http://www.openwall.com/lists/oss-security/2021/02/19/4
- https://lists.debian.org/debian-lts-announce/2021/02/msg00030.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HCQTCSP6SCVIYNIRUJC5X7YBVUHPLSC4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NODWHDIFBQE5RU5PUWUVE47JOT5VCMJ2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MP572OLHMS7MZO4KUPSCIMSZIA5IZZ62/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MNUN5SOMFL2BBKP6ZAICIIUPQKZDMGYO/
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FONHJIOZOFD7CD35KZL6SVBUTMBPGZGA/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KJXCMHLY7H3FIYLE4OKDYUILU2CCRUCZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YKKDLXL3UEZ3J426C2XTBS63AHE46SM/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TFTELUMWZE3KV3JB2H5EE6VFRZFRD5MV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OAGSWNGZJ6HQ5ISA67SNMK3CJRKICET7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NJSCSN722JO2E2AGPWD4NTGVELVRPB4R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HZTM7KLHFCE3LWSEVO2NAFLUHMGYMCRY/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EPYWWFDV22CJ5AOH5VCE72DOASZZ255/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IHQDU7NXA7EWAE4W7VO6MURVJIULEPPR/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W2LSKBEFI5SYEY5FM6ICZVZM5WRQUCS4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/46N6A52EGSXHJYCZWVMBJJIH4NWIV2B5/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LVNH6Z24IG3E67ZCQGGJ46FZB4XFLQNZ/
- https://lists.debian.org/debian-lts-announce/2021/04/msg00005.html
- https://lists.debian.org/debian-lts-announce/2021/04/msg00015.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/N6VXJZSZ6N64AILJX4CTMACYGQGHHD5C/
- https://security.gentoo.org/glsa/202104-04
- https://lists.apache.org/thread.html/ra8ce70088ba291f358e077cafdb14d174b7a1ce9a9d86d1b332d6367%40%3Cusers.airflow.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/05/01/2
- https://lists.apache.org/thread.html/rc005f4de9d9b0ba943ceb8ff5a21a5c6ff8a9df52632476698d99432%40%3Cannounce.apache.org%3E
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SGIY6I4YS3WOXAK4SXKIEOC2G4VZKIR7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RSLQD5CCM75IZGAMBDGUZEATYU5YSGJ7/
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://security.netapp.com/advisory/ntap-20210326-0004/
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://lists.debian.org/debian-lts-announce/2023/09/msg00022.html
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |