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.
Conclusion & alert: CVE-2021-23336 is rated Exploit Available (56.3/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.28%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-12-28 | 0.38% | 0.28% | -0.11% |
| 2 | 2025-12-27 | 0.31% | 0.38% | +0.07% |
| 3 | 2025-11-21 | — | 0.31% | — |
Full EPSS history (30 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.9 | 3.1 | MEDIUM |
|
1.6 | 4.2 | [email protected] |
| 5.9 | 3.1 | MEDIUM |
|
1.6 | 4.2 | [email protected] |
| 4.0 | 2.0 | MEDIUM |
|
4.9 | 4.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2021-23336: 2 source package rows (py3-django, python3); 15 state rows across 15 repos (3.12-main, 3.17-community, 3.17-main, 3.18-community, 3.18-main, 3.19-community, 3.19-main, 3.20-community, 3.20-main, 3.21-community, 3.21-main, 3.22-community, 3.22-main, edge-community, edge-main); fixed 15, open 0. | https://security.alpinelinux.org/vuln/CVE-2021-23336 |
debian
|
not yet assigned | CVE-2021-23336 not yet assigned priority: Debian including 4 source packages (pypy3, python-django, python2.7, python3.9), 12 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 12. | https://security-tracker.debian.org/tracker/CVE-2021-23336 |
gentoo
|
normal | CVE-2021-23336: 1 GLSA(s) (202104-04), 1 atom(s) (dev-lang/python); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-23336 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2021-23336 |
suse
|
medium | CVE-2021-23336 severity moderate: SUSE including 766 source package names (0.1.75:libpython3_6m1_0-3.6.13-3.78.1, 0.1.75:python3-3.6.13-3.78.1, …), 1619 product×package rows across 123 product lines (Container caasp/v4/389-ds, Container caasp/v4/hyperkube, … (123 product lines)): Fixed 1459, Known Affected 135, Known Not Affected 25. | https://www.suse.com/security/cve/CVE-2021-23336/ |
ubuntu
|
low | CVE-2021-23336 low priority: Ubuntu including 8 source packages (python-django, python2.7, …), 104 status rows across 13 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 63, ignored 17, released 17, not-affected 4, needs-triage 3. | https://ubuntu.com/security/CVE-2021-23336 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| python | python | < 3.6.13 | cpe:2.3:a:python:python:*:*:*:*:*:*:*:* |
| python | python | >= 3.7.0, < 3.7.10 | cpe:2.3:a:python:python:*:*:*:*:*:*:*:* |
| python | python | >= 3.8.0, < 3.8.8 | cpe:2.3:a:python:python:*:*:*:*:*:*:*:* |
| python | python | >= 3.9.0, < 3.9.2 | cpe:2.3:a:python:python:*:*:*:*:*:*:*:* |
| fedoraproject | fedora | 32 | cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* |
| fedoraproject | fedora | 33 | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
| fedoraproject | fedora | 34 | cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* |
| debian | debian_linux | 9.0 | cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* |
| netapp | cloud_backup | — | cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:* |
| netapp | inventory_collect_tool | — | cpe:2.3:a:netapp:inventory_collect_tool:-:*:*:*:*:*:*:* |
| netapp | ontap_select_deploy_administration_utility | — | cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:* |
| netapp | snapcenter | — | cpe:2.3:a:netapp:snapcenter:-:*:*:*:*:*:*:* |
| djangoproject | django | >= 2.2, < 2.2.19 | cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:* |
| djangoproject | django | >= 3.0, < 3.0.13 | cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:* |
| djangoproject | django | >= 3.1, < 3.1.7 | cpe:2.3:a:djangoproject:django:*:*:*:*:*:*:*:* |
| oracle | communications_offline_mediation_controller | 12.0.0.3.0 | cpe:2.3:a:oracle:communications_offline_mediation_controller:12.0.0.3.0:*:*:*:*:*:*:* |
| oracle | communications_pricing_design_center | 12.0.0.3.0 | cpe:2.3:a:oracle:communications_pricing_design_center:12.0.0.3.0:*:*:*:*:*:*:* |
| oracle | enterprise_manager_ops_center | 12.4.0.0 | cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:* |
| oracle | zfs_storage_appliance | 8.8 | cpe:2.3:o:oracle:zfs_storage_appliance:8.8:*:*:*:*:*:*:* |