CVE-2020-8492Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks agains…
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It affects Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP and 7 other products. Add what you run to find out whether that includes you.
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Python 2.7 through 2.7.17, 3.5 through 3.5.9, 3.6 through 3.6.10, 3.7 through 3.7.6, and 3.8 through 3.8.1 allows an HTTP server to conduct Regular Expression Denial of Service (ReDoS) attacks against a client because of urllib.request.AbstractBasicAuthHandler catastrophic backtracking.
- CVSS
- 6.5 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-400
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mitre
- NVD analysis
- Modified
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 9, 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 | from 2.7.0 through 2.7.17; from 3.5.0 through 3.5.9; from 3.6.0 through 3.6.10; from 3.7.0 through 3.7.6; from 3.8.0 through 3.8.1 | NVD |
opensuse leap opensuse:leap | 15.1 | NVD |
canonical ubuntu_linux canonical:ubuntu_linux | 12.04; 14.04; 16.04; 18.04; 19.10; 20.04 | NVD |
fedoraproject fedora fedoraproject:fedora | 31; 32 | NVD |
debian debian_linux debian:debian_linux | 9.0 | NVD |
References
- https://bugs.python.org/issue39503issue-tracking, vendor-advisory
- https://python-security.readthedocs.io/vuln/urllib-basic-auth-regex.htmlexploit, third-party-advisory
- https://github.com/python/cpython/pull/18284patch, third-party-advisory
- https://security.netapp.com/advisory/ntap-20200221-0001/third-party-advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00003.htmlvendor-advisory, third-party-advisory
- https://usn.ubuntu.com/4333-1/vendor-advisory, third-party-advisory
- https://usn.ubuntu.com/4333-2/vendor-advisory, third-party-advisory
- https://security.gentoo.org/glsa/202005-09vendor-advisory, third-party-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APGWEMYZIY5VHLCSZ3HD67PA5Z2UQFGH/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WOKDEXLYW5UQ4S7PA7E37IITOC7C56J/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UESGYI5XDAHJBATEZN3MHNDUBDH47AS6/vendor-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A5NSAX4SC3V64PGZUPH7PRDLSON34Q5A/vendor-advisory
- https://lists.debian.org/debian-lts-announce/2020/07/msg00011.htmlmailing-list, third-party-advisory
- https://lists.apache.org/thread.html/rdb31a608dd6758c6093fd645aea3fbf022dd25b37109b6aaea5bc0b5%40%3Ccommits.cassandra.apache.org%3Emailing-list
- https://lists.apache.org/thread.html/rfec113c733162b39633fd86a2d0f34bf42ac35f711b3ec1835c774da%40%3Ccommits.cassandra.apache.org%3Emailing-list
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.htmlmailing-list
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.