{"id":"UBUNTU-CVE-2023-23934","details":"Werkzeug is a comprehensive WSGI web application library. Browsers may allow \"nameless\" cookies that look like `=value` instead of `key=value`. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like `=__Host-test=bad` for another subdomain. Werkzeug prior to 2.2.3 will parse the cookie `=__Host-test=bad` as __Host-test=bad`. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key. The issue is fixed in Werkzeug 2.2.3.","modified":"2026-01-30T02:26:52.331855Z","published":"2023-02-14T20:15:00Z","related":["USN-5948-1","USN-5948-2"],"upstream":["CVE-2023-23934"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2023-23934"},{"type":"REPORT","url":"https://github.com/pallets/werkzeug/security/advisories/GHSA-px8h-6qxv-m22q"},{"type":"REPORT","url":"https://github.com/pallets/werkzeug/commit/cf275f42acad1b5950c50ffe8ef58fe62cdce028"},{"type":"REPORT","url":"https://github.com/pallets/werkzeug/releases/tag/2.2.3"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5948-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5948-2"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2023-23934"}],"affected":[{"package":{"name":"python-werkzeug","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/python-werkzeug@0.10.4+dfsg1-1ubuntu1.2+esm1?arch=source&distro=esm-infra/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.10.4+dfsg1-1ubuntu1.2+esm1"}]}],"versions":["0.10.4+dfsg1-1ubuntu1","0.10.4+dfsg1-1ubuntu1.1","0.10.4+dfsg1-1ubuntu1.2"],"ecosystem_specific":{"binaries":[{"binary_name":"python-werkzeug","binary_version":"0.10.4+dfsg1-1ubuntu1.2+esm1"},{"binary_name":"python3-werkzeug","binary_version":"0.10.4+dfsg1-1ubuntu1.2+esm1"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-23934.json"}},{"package":{"name":"python-werkzeug","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/python-werkzeug@0.14.1+dfsg1-1ubuntu0.2?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.14.1+dfsg1-1ubuntu0.2"}]}],"versions":["0.12.2+dfsg1-2","0.13+dfsg1-1","0.14.1+dfsg1-1","0.14.1+dfsg1-1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"python-werkzeug","binary_version":"0.14.1+dfsg1-1ubuntu0.2"},{"binary_name":"python3-werkzeug","binary_version":"0.14.1+dfsg1-1ubuntu0.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-23934.json"}},{"package":{"name":"python-werkzeug","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python-werkzeug@0.16.1+dfsg1-2ubuntu0.1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.16.1+dfsg1-2ubuntu0.1"}]}],"versions":["0.14.1+dfsg1-4","0.15.6+dfsg1-1","0.16.0+dfsg1-1","0.16.1+dfsg1-1ubuntu1","0.16.1+dfsg1-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-werkzeug","binary_version":"0.16.1+dfsg1-2ubuntu0.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-23934.json"}},{"package":{"name":"python-werkzeug","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-werkzeug@2.0.2+dfsg1-1ubuntu0.22.04.1?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.2+dfsg1-1ubuntu0.22.04.1"}]}],"versions":["1.0.1+dfsg1-2","2.0.2+dfsg1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-werkzeug","binary_version":"2.0.2+dfsg1-1ubuntu0.22.04.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-23934.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}