{"id":"CVE-2023-23934","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-23934","generatedAt":"2026-10-27T19:39:21.681Z","title":"Browsers may allow \"nameless\" cookies that look like `=value` instead of `key=value`.","description":"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.","published":"2023-02-14T20:15:17.000Z","lastModified":"2026-06-17T05:38:19.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":3.5,"severity":"LOW","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"},"cwe":["CWE-20"],"affected":["palletsprojects/werkzeug"],"epss":{"score":0.00507,"percentile":0.42989,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.51%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/pallets/werkzeug/commit/cf275f42acad1b5950c50ffe8ef58fe62cdce028","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/pallets/werkzeug/releases/tag/2.2.3","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/pallets/werkzeug/security/advisories/GHSA-px8h-6qxv-m22q","tags":["Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://security.netapp.com/advisory/ntap-20230818-0003/","source":"security-advisories@github.com"},{"url":"https://www.debian.org/security/2023/dsa-5470","source":"security-advisories@github.com"},{"url":"https://github.com/pallets/werkzeug/commit/cf275f42acad1b5950c50ffe8ef58fe62cdce028","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/pallets/werkzeug/releases/tag/2.2.3","tags":["Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/pallets/werkzeug/security/advisories/GHSA-px8h-6qxv-m22q","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20230818-0003/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2023/dsa-5470","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-23934","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}