CVE-2018-20852
At a glance
- Severity
- MEDIUM 4.3
- EPSS
- EPSS 3.67 % · percentile 90 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mitre
- NVD status
- Modified
Description
http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can be tricked into sending existing cookies to the wrong server. An attacker may abuse this flaw by using a server with a hostname that has another valid hostname as a suffix (e.g., pythonicexample.com to steal cookies for example.com). When a program uses http.cookiejar.DefaultPolicy and tries to do an HTTP connection to an attacker-controlled server, existing cookies can be leaked to the attacker. This affects 2.x through 2.7.16, 3.x before 3.4.10, 3.5.x before 3.5.7, 3.6.x before 3.6.9, and 3.7.x before 3.7.3.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N | CISA-ADP |
| CVSS 3.1 | MEDIUM 4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 3.0 | MEDIUM 5.3 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 2.0 | MEDIUM 5.0 | AV:N/AC:L/Au:N/C:P/I:N/A:N | NVD · nvd@nist.gov (Primary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2018-13392
- GCVE · GCVE-0-2018-20852
CERT-FR advisories
- CERTFR-2026-AVI-0395 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2022-AVI-928 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2022-AVI-267 — Multiples vulnérabilités dans Juniper Networks Junos Space · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 2.0 ≤ 2.7.16cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.0.0 < 3.4.10cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.5.0 < 3.5.7cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.6.0 < 3.6.9cpe:2.3:a:python:python:*:*:*:*:*:*:*:*≥ 3.7.0 < 3.7.3
Affected products
| Product | Versions |
|---|---|
| affected n/a |
References
- https://bugs.python.org/issue35121
- https://python-security.readthedocs.io/vuln/cookie-domain-check.html
- https://lists.debian.org/debian-lts-announce/2019/08/msg00022.html
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00071.html
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00074.html
- https://lists.debian.org/debian-lts-announce/2019/08/msg00040.html
- https://usn.ubuntu.com/4127-2/
- https://usn.ubuntu.com/4127-1/
- https://access.redhat.com/errata/RHSA-2019:3725
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K7HNVIFMETMFWWWUNTB72KYJYXCZOS5V/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZBTGPBUABGXZ7WH7677OEM3NSP6ZEA76/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/COATURTCY7G67AYI6UDV5B2JZTBCKIDX/
- https://access.redhat.com/errata/RHSA-2019:3948
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html
- https://security.gentoo.org/glsa/202003-26
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |