CVE-2023-23934
Wrkzeug's incorrect parsing of nameless cookies leads to __Host- cookies bypass
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Low2.6 | CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Low3.5 | CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.51% · top 57% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 2.6.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIWerkzeugGHSA-px8h-6qxv-m22q (opens in a new tab)
References (5)
- https://github.com/pallets/werkzeug/security/advisories/GHSA-px8h-6qxv-m22q (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/pallets/werkzeug/commit/cf275f42acad1b5950c50ffe8ef58fe62cdce028 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/pallets/werkzeug/releases/tag/2.2.3 (opens in a new tab)x_refsource_MISCx_transferred
- https://www.debian.org/security/2023/dsa-5470 (opens in a new tab)x_transferred
- https://security.netapp.com/advisory/ntap-20230818-0003/ (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-px8h-6qxv-m22q (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-23934)Record last updated .