{"id":"CVE-2024-35225","aliases":["GHSA-fvcq-4x64-hqxr","PYSEC-2024-236"],"url":"https://o3.security/vulnerability/CVE-2024-35225","summary":"Jupyter Server Proxy has a reflected XSS issue in host parameter","details":"### Impact\n\nThere is a reflected cross-site scripting (XSS) issue in `jupyter-server-proxy`[1]. The `/proxy` endpoint accepts a `host` path segment in the format `/proxy/<host>`. When this endpoint is called with an invalid `host` value, `jupyter-server-proxy` replies with a response that includes the value of `host`, without sanitization [2]. A third-party actor can leverage this by sending a phishing link with an invalid `host` value containing custom JavaScript to a user. When the user clicks this phishing link, the browser renders the response of `GET /proxy/<host>`, which runs the custom JavaScript contained in `host` set by the actor.\nAs any arbitrary JavaScript can be run after the user clicks on a phishing link, this issue permits extensive access to the user's JupyterLab instance for an actor. This issue exists in the latest release of `jupyter-server-proxy`, currently `v4.1.2`.\n**Impacted versions:** `>=3.0.0,<=4.1.2`\n\n### Patches\n\nThe patches are included in `==4.2.0` and `==3.2.4`.\n\n### Workarounds\n\nServer operators who are unable to upgrade can disable the `jupyter-server-proxy` extension with:\n\n```\njupyter server extension disable jupyter-server-proxy\n```\n\n### References\n\n[1] : https://github.com/jupyterhub/jupyter-server-proxy/\n[2] : https://github.com/jupyterhub/jupyter-server-proxy/blob/62a290f08750f7ae55a0c29ca339c9a39a7b2a7b/jupyter_server_proxy/handlers.py#L328","published":"2024-06-11T21:45:57.596Z","modified":"2026-08-12T03:51:26.116309481Z","cvss":{"score":9.6,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"},"epss":{"score":0.00446,"percentile":0.38013,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"jupyter-server-proxy","fixedVersion":"3.2.4"},{"ecosystem":"PyPI","name":"jupyter-server-proxy","fixedVersion":"4.2.0"}],"fix":{"url":"https://github.com/jupyterhub/jupyter-server-proxy/commit/7abc9dc5bbb0b4b440548a5375261b8b8192fc22","label":"jupyterhub/jupyter-server-proxy@7abc9dc"},"references":[{"type":"WEB","url":"https://github.com/jupyterhub/jupyter-server-proxy/blob/62a290f08750f7ae55a0c29ca339c9a39a7b2a7b/jupyter_server_proxy/handlers.py#L328"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/35xxx/CVE-2024-35225.json"},{"type":"ADVISORY","url":"https://github.com/jupyterhub/jupyter-server-proxy/security/advisories/GHSA-fvcq-4x64-hqxr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-35225"},{"type":"FIX","url":"https://github.com/jupyterhub/jupyter-server-proxy/commit/7abc9dc5bbb0b4b440548a5375261b8b8192fc22"},{"type":"FIX","url":"https://github.com/jupyterhub/jupyter-server-proxy/commit/ff78128087e73fb9d0909e1366f8bf051e8ea878"},{"type":"PACKAGE","url":"https://github.com/jupyterhub/jupyter-server-proxy"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/jupyter-server-proxy/PYSEC-2024-236.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:26.116309481Z"}}