{"id":"CVE-2018-20852","state":"PUBLISHED","title":"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 cookie","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.","publishedAt":"2019-07-13T20:29:42.000Z","updatedAt":"2026-10-07T18:24:46.612Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","source":"CISA-ADP"},"assigner":"mitre","products":["n/a n/a"],"affected":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}],"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"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T19:44:39.424Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2018/20xxx/CVE-2018-20852.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2018-20852","state":"PUBLISHED","datePublished":"2019-07-13T20:29:42.000Z","dateUpdated":"2026-10-07T18:24:46.612Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2019-07-13T00:00:00.000Z"},"containers":{"cna":{"descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}],"references":[{"url":"https://bugs.python.org/issue35121","tags":["x_refsource_MISC"]},{"url":"https://python-security.readthedocs.io/vuln/cookie-domain-check.html","tags":["x_refsource_MISC"]},{"url":"https://lists.debian.org/debian-lts-announce/2019/08/msg00022.html","name":"[debian-lts-announce] 20190817 [SECURITY] [DLA 1889-1] python3.4 security update","tags":["mailing-list","x_refsource_MLIST"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00071.html","name":"openSUSE-SU-2019:1988","tags":["vendor-advisory","x_refsource_SUSE"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00074.html","name":"openSUSE-SU-2019:1989","tags":["vendor-advisory","x_refsource_SUSE"]},{"url":"https://lists.debian.org/debian-lts-announce/2019/08/msg00040.html","name":"[debian-lts-announce] 20190831 [SECURITY] [DLA 1906-1] python2.7 security update","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://usn.ubuntu.com/4127-2/","name":"USN-4127-2","tags":["vendor-advisory","x_refsource_UBUNTU"]},{"url":"https://usn.ubuntu.com/4127-1/","name":"USN-4127-1","tags":["vendor-advisory","x_refsource_UBUNTU"]},{"url":"https://access.redhat.com/errata/RHSA-2019:3725","name":"RHSA-2019:3725","tags":["vendor-advisory","x_refsource_REDHAT"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K7HNVIFMETMFWWWUNTB72KYJYXCZOS5V/","name":"FEDORA-2019-0d3fcae639","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZBTGPBUABGXZ7WH7677OEM3NSP6ZEA76/","name":"FEDORA-2019-74ba24605e","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/COATURTCY7G67AYI6UDV5B2JZTBCKIDX/","name":"FEDORA-2019-758824a3ff","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://access.redhat.com/errata/RHSA-2019:3948","name":"RHSA-2019:3948","tags":["vendor-advisory","x_refsource_REDHAT"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html","name":"openSUSE-SU-2020:0086","tags":["vendor-advisory","x_refsource_SUSE"]},{"url":"https://security.gentoo.org/glsa/202003-26","name":"GLSA-202003-26","tags":["vendor-advisory","x_refsource_GENTOO"]},{"url":"https://www.oracle.com/security-alerts/cpuapr2020.html","tags":["x_refsource_MISC"]},{"url":"https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html","name":"[debian-lts-announce] 20200715 [SECURITY] [DLA 2280-1] python3.5 security update","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html","name":"[debian-lts-announce] 20200822 [SECURITY] [DLA 2337-1] python2.7 security update","tags":["mailing-list","x_refsource_MLIST"]}],"problemTypes":[{"descriptions":[{"description":"n/a","lang":"en","type":"text"}]}],"providerMetadata":{"shortName":"mitre","dateUpdated":"2020-08-22T16:06:16.000Z","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca"},"x_legacyV4Record":{"CVE_data_meta":{"ASSIGNER":"cve@mitre.org","ID":"CVE-2018-20852","STATE":"PUBLIC"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"n/a","version":{"version_data":[{"version_value":"n/a"}]}}]},"vendor_name":"n/a"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"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."}]},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"n/a"}]}]},"references":{"reference_data":[{"name":"https://bugs.python.org/issue35121","refsource":"MISC","url":"https://bugs.python.org/issue35121"},{"name":"https://python-security.readthedocs.io/vuln/cookie-domain-check.html","refsource":"MISC","url":"https://python-security.readthedocs.io/vuln/cookie-domain-check.html"},{"name":"[debian-lts-announce] 20190817 [SECURITY] [DLA 1889-1] python3.4 security update","refsource":"MLIST","url":"https://lists.debian.org/debian-lts-announce/2019/08/msg00022.html"},{"name":"openSUSE-SU-2019:1988","refsource":"SUSE","url":"http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00071.html"},{"name":"openSUSE-SU-2019:1989","refsource":"SUSE","url":"http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00074.html"},{"name":"[debian-lts-announce] 20190831 [SECURITY] [DLA 1906-1] python2.7 security update","refsource":"MLIST","url":"https://lists.debian.org/debian-lts-announce/2019/08/msg00040.html"},{"name":"USN-4127-2","refsource":"UBUNTU","url":"https://usn.ubuntu.com/4127-2/"},{"name":"USN-4127-1","refsource":"UBUNTU","url":"https://usn.ubuntu.com/4127-1/"},{"name":"RHSA-2019:3725","refsource":"REDHAT","url":"https://access.redhat.com/errata/RHSA-2019:3725"},{"name":"FEDORA-2019-0d3fcae639","refsource":"FEDORA","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/K7HNVIFMETMFWWWUNTB72KYJYXCZOS5V/"},{"name":"FEDORA-2019-74ba24605e","refsource":"FEDORA","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZBTGPBUABGXZ7WH7677OEM3NSP6ZEA76/"},{"name":"FEDORA-2019-758824a3ff","refsource":"FEDORA","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/COATURTCY7G67AYI6UDV5B2JZTBCKIDX/"},{"name":"RHSA-2019:3948","refsource":"REDHAT","url":"https://access.redhat.com/errata/RHSA-2019:3948"},{"name":"openSUSE-SU-2020:0086","refsource":"SUSE","url":"http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html"},{"name":"GLSA-202003-26","refsource":"GENTOO","url":"https://security.gentoo.org/glsa/202003-26"},{"name":"https://www.oracle.com/security-alerts/cpuapr2020.html","refsource":"MISC","url":"https://www.oracle.com/security-alerts/cpuapr2020.html"},{"name":"[debian-lts-announce] 20200715 [SECURITY] [DLA 2280-1] python3.5 security update","refsource":"MLIST","url":"https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html"},{"name":"[debian-lts-announce] 20200822 [SECURITY] [DLA 2337-1] python2.7 security update","refsource":"MLIST","url":"https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html"}]}}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://bugs.python.org/issue35121","tags":["x_refsource_MISC","x_transferred"]},{"url":"https://python-security.readthedocs.io/vuln/cookie-domain-check.html","tags":["x_refsource_MISC","x_transferred"]},{"url":"https://lists.debian.org/debian-lts-announce/2019/08/msg00022.html","name":"[debian-lts-announce] 20190817 [SECURITY] [DLA 1889-1] python3.4 security update","tags":["mailing-list","x_refsource_MLIST","x_transferred"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00071.html","name":"openSUSE-SU-2019:1988","tags":["vendor-advisory","x_refsource_SUSE","x_transferred"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00074.html","name":"openSUSE-SU-2019:1989","tags":["vendor-advisory","x_refsource_SUSE","x_transferred"]},{"url":"https://lists.debian.org/debian-lts-announce/2019/08/msg00040.html","name":"[debian-lts-announce] 20190831 [SECURITY] [DLA 1906-1] python2.7 security update","tags":["mailing-list","x_refsource_MLIST","x_transferred"]},{"url":"https://usn.ubuntu.com/4127-2/","name":"USN-4127-2","tags":["vendor-advisory","x_refsource_UBUNTU","x_transferred"]},{"url":"https://usn.ubuntu.com/4127-1/","name":"USN-4127-1","tags":["vendor-advisory","x_refsource_UBUNTU","x_transferred"]},{"url":"https://access.redhat.com/errata/RHSA-2019:3725","name":"RHSA-2019:3725","tags":["vendor-advisory","x_refsource_REDHAT","x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K7HNVIFMETMFWWWUNTB72KYJYXCZOS5V/","name":"FEDORA-2019-0d3fcae639","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZBTGPBUABGXZ7WH7677OEM3NSP6ZEA76/","name":"FEDORA-2019-74ba24605e","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/COATURTCY7G67AYI6UDV5B2JZTBCKIDX/","name":"FEDORA-2019-758824a3ff","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred"]},{"url":"https://access.redhat.com/errata/RHSA-2019:3948","name":"RHSA-2019:3948","tags":["vendor-advisory","x_refsource_REDHAT","x_transferred"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html","name":"openSUSE-SU-2020:0086","tags":["vendor-advisory","x_refsource_SUSE","x_transferred"]},{"url":"https://security.gentoo.org/glsa/202003-26","name":"GLSA-202003-26","tags":["vendor-advisory","x_refsource_GENTOO","x_transferred"]},{"url":"https://www.oracle.com/security-alerts/cpuapr2020.html","tags":["x_refsource_MISC","x_transferred"]},{"url":"https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html","name":"[debian-lts-announce] 20200715 [SECURITY] [DLA 2280-1] python3.5 security update","tags":["mailing-list","x_refsource_MLIST","x_transferred"]},{"url":"https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html","name":"[debian-lts-announce] 20200822 [SECURITY] [DLA 2337-1] python2.7 security update","tags":["mailing-list","x_refsource_MLIST","x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-05T12:12:29.756Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":4.3,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","integrityImpact":"NONE","userInteraction":"REQUIRED","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"LOW"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-10-07T18:24:08.871365Z","id":"CVE-2018-20852","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","type":"CWE","lang":"en","description":"CWE-20 Improper Input Validation"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-07T18:24:46.612Z"}}]}}}