CVE-2021-23336

mediumpriority · track · 38EPSS 0.407 · 99 %ileDEEUNLRUUS
grimoire priorityP1 · Urgent
Exploitable?
—
no known exploitation
Likely / severe?
40.7% (99th) EPSS
CVSS 4 · medium
Is it mine?
81 products
Check your exposure
Who says so?
8 sources
cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-22

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

5.9
010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04mediumAV:N/AC:H/Au:N/C:N/I:P/A:Pprimary · NVD / NIST USexploitability 4.9 · impact 4.9
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:Hprimary · NVD / NIST USexploitability 1.6 · impact 4.2
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H/E:P/RL:U/RC:Csecondary · CISA US
v3.15.9mediumAV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:Hsecondary · FSTEC (BDU) RU
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H/E:P/RL:U/RC:Csecondary · ENISA EU
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:Hsecondary · report@snyk.ioexploitability 1.6 · impact 4.2
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H/E:P/RL:U/RC:Csecondary · Siemens ProductCERT DE
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H/E:Hsecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

05

affected products (81)

Products and version ranges known to be affected.

showing 20 of 81
06

advisories (10)

Vendor and ecosystem advisories describing this.

  • NCSC-2024-0339Kwetsbaarheden verholpen in Microsoft MarinerNL2024-08-13csaf · ncsc_nlNL

    Microsoft heeft kwetsbaarheden verholpen in Mariner (Azure Linux).

  • SSA-398330SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.52023-12-12csaf · siemens_psirtDE

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 are no longer maintained and there won't be any update to the CVE list anymore. Please update to the latest version. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 (https://cert-portal.siemens.com/productcert/html/ssb-439005.html).

  • WID-SEC-W-2022-0141Python: Schwachstelle ermöglicht Darstellen falscher InformationenDeutsch2021-02-15csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Python ausnutzen, um falsche Informationen darzustellen.

  • WID-SEC-W-2025-0227IBM QRadar SIEM: Mehrere SchwachstellenDeutsch2021-11-30csaf · cert_bundDE

    Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um seine Privilegien zu erweitern, Administratorrechte zu erlangen, beliebigen Programmcode auszuführen, Informationen offenzulegen, Dateien zu manipulieren oder Sicherheitsvorkehrungen zu umgehen.

  • ICSA-23-348-10Siemens SIMATIC S7-15002023-12-12icsa · cisa_csaf_otUS

    Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 ( https://cert-portal.siemens.com/productcert/html/ssb-439005.html).

  • BIT-django-2021-23336Web Cache Poisoning2024-03-06vendor · osvUS

    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.

  • BIT-libpython-2021-23336Web Cache Poisoning2025-08-11vendor · osvUS

    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.

  • BIT-python-2021-23336Web Cache Poisoning2024-03-06vendor · osvUS

    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.

  • BIT-python-min-2021-23336Web Cache Poisoning2025-01-16vendor · osvUS

    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.

  • PSF-2021-1urllib parse_qsl(): Web cache poisoning - semicolon as a query args separator2021-02-15vendor · osvUS

    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.

07

also known as (10)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

10

references (149)

External citations — patches, advisories, analysis.

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