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Medium 5.9Published Feb 15, 2021
CVE-2021-23336Web Cache Poisoning
Updated under an hour ago ()
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It affects Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP and 14 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 5.9 MEDIUM (v3.1, CNA)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
- Weakness (CWE)
- CWE-444
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- snyk
- NVD analysis
- Modified
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 14, 2026
Affected products
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
python python python:python | before 3.6.13; from 3.7.0 before 3.7.10; from 3.8.0 before 3.8.8; from 3.9.0 before 3.9.2 | NVD |
fedoraproject fedora fedoraproject:fedora | 32; 33; 34 | NVD |
debian debian_linux debian:debian_linux | 9.0 | NVD |
netapp cloud_backup netapp:cloud_backup | all versions | NVD |
netapp inventory_collect_tool netapp:inventory_collect_tool | all versions | NVD |
netapp ontap_select_deploy_administration_utility netapp:ontap_select_deploy_administration_utility | all versions | NVD |
netapp snapcenter netapp:snapcenter | all versions | NVD |
djangoproject django djangoproject:django | from 2.2 before 2.2.19; from 3.0 before 3.0.13; from 3.1 before 3.1.7 | NVD |
oracle communications_offline_mediation_controller oracle:communications_offline_mediation_controller | 12.0.0.3.0 | NVD |
oracle communications_pricing_design_center oracle:communications_pricing_design_center | 12.0.0.3.0 | NVD |
oracle enterprise_manager_ops_center oracle:enterprise_manager_ops_center | 12.4.0.0 | NVD |
oracle zfs_storage_appliance oracle:zfs_storage_appliance | 8.8 | NVD |
References
- https://snyk.io/vuln/SNYK-UPSTREAM-PYTHONCPYTHON-1074933
- https://github.com/python/cpython/pull/24297patch, third-party-advisory
- https://snyk.io/blog/cache-poisoning-in-popular-open-source-packages/
- http://www.openwall.com/lists/oss-security/2021/02/19/4mailing-list, patch, third-party-advisory
- https://lists.debian.org/debian-lts-announce/2021/02/msg00030.htmlmailing-list, third-party-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HCQTCSP6SCVIYNIRUJC5X7YBVUHPLSC4/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NODWHDIFBQE5RU5PUWUVE47JOT5VCMJ2/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MP572OLHMS7MZO4KUPSCIMSZIA5IZZ62/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MNUN5SOMFL2BBKP6ZAICIIUPQKZDMGYO/vendor-advisory
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3Emailing-list
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FONHJIOZOFD7CD35KZL6SVBUTMBPGZGA/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KJXCMHLY7H3FIYLE4OKDYUILU2CCRUCZ/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YKKDLXL3UEZ3J426C2XTBS63AHE46SM/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TFTELUMWZE3KV3JB2H5EE6VFRZFRD5MV/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OAGSWNGZJ6HQ5ISA67SNMK3CJRKICET7/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NJSCSN722JO2E2AGPWD4NTGVELVRPB4R/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HZTM7KLHFCE3LWSEVO2NAFLUHMGYMCRY/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EPYWWFDV22CJ5AOH5VCE72DOASZZ255/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IHQDU7NXA7EWAE4W7VO6MURVJIULEPPR/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W2LSKBEFI5SYEY5FM6ICZVZM5WRQUCS4/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/46N6A52EGSXHJYCZWVMBJJIH4NWIV2B5/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LVNH6Z24IG3E67ZCQGGJ46FZB4XFLQNZ/vendor-advisory
- https://lists.debian.org/debian-lts-announce/2021/04/msg00005.htmlmailing-list, third-party-advisory
- https://lists.debian.org/debian-lts-announce/2021/04/msg00015.htmlmailing-list, third-party-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/N6VXJZSZ6N64AILJX4CTMACYGQGHHD5C/vendor-advisory
- http://www.openwall.com/lists/oss-security/2021/05/01/2mailing-list, third-party-advisory
- 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
- https://lists.debian.org/debian-lts-announce/2023/09/msg00022.html
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