ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2021-23336

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…

Published Feb 15, 2021 · catalog updated Oct 14, 2026 · the affected product

Check this week

CVE-2021-23336 is not in CISA KEV. FIRST estimates a 40.74% chance of exploitation in the next 30 days. Check whether you run the affected product.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
40.74%
Remediation
Advisory link
Affected products
cpe debian/debian linux · cpe djangoproject/django · cpe fedoraproject/fedora · cpe netapp/cloud backup · cpe oracle/communications offline mediation controller · cpe python/python

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe debian/debian linux9.0
  • cpe djangoproject/djangoversion unspecified
  • cpe fedoraproject/fedora32
  • cpe fedoraproject/fedora33
  • cpe fedoraproject/fedora34
  • cpe netapp/cloud backupversion unspecified
  • cpe oracle/communications offline mediation controller12.0.0.3.0
  • cpe python/pythonversion unspecified

How to fix CVE-2021-23336

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-23336 is not in CISA KEV. FIRST estimates a 40.74% chance of exploitation in the next 30 days. Check whether you run the affected product.

Which versions are affected?

Compare what you have installed with debian/debian linux 9.0; oracle/communications offline mediation controller 12.0.0.3.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-444: HTTP Request Smuggling. EPSS 40.74%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 15, 2021 · NIST NVD

    Detected

    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

  2. Oct 14, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2021-23336

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-23336

    30-day exploitation probability 40.74%

    first.org
  • NIST NVDVulnerability recordCVE-2021-23336

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 21, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.