{"answers":{"affected":"3 open source packages ship an affected version, including jupyter-server. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-40934 in the wild and no public exploit code.","fix":"Upgrade jupyter-server to 2.18.0 or later.","what":"CVE-2026-40934 is a high-severity authentication bypass vulnerability in jupyter-server jupyter_server, published on 5 May 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-40934 and fix it if it is affected.\n\nWhat it is: CVE-2026-40934 is a high-severity authentication bypass vulnerability in jupyter-server jupyter_server, published on 5 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-40934 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- jupyter-server (PyPI): affected all versions; fixed in 2.18.0\n- jupyter-server (PyPI): affected all versions; fixed in 2.18.0\n- jupyter-server (PyPI): affected all versions; fixed in 2.18.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-40934/ (Markdown: https://insights.sbomify.com/CVE-2026-40934/index.md)","id":"CVE-2026-40934","markdown":"https://insights.sbomify.com/CVE-2026-40934/index.md","name":"CVE-2026-40934","record":{"aliases":["CLEANSTART-2026-HV39439","CLEANSTART-2026-PZ41099","DEBIAN-CVE-2026-40934","GHSA-5mrq-x3x5-8v8f","PYSEC-2026-69","UBUNTU-CVE-2026-40934"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["account_takeover","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Jupyter Server","requires_auth":"low_privilege","summary":"Attackers retain authenticated access after password resets because Jupyter Server fails to rotate the cookie signing secret, allowing session hijacking.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"jupyter_server","vendor":"jupyter"}],"cvss":{"score":7.6,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-613","name":"DEPRECATED: Insufficient Session Expiration"}],"description":"Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the secret used to sign authentication cookies is persisted to a static file at ~/.local/share/jupyter/runtime/jupyter_cookie_secret and is never rotated when a user changes their password. After a password reset and server restart, any previously issued authentication cookie remains cryptographically valid because the signing key has not changed. An attacker who has captured a session cookie through any means retains full authenticated access to the server regardless of subsequent password changes. This affects deployments using password-based authentication, particularly shared or public-facing servers where credential rotation is expected to revoke existing sessions. This issue has been fixed in version 2.18.0.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"jupyter-server authentication cookies remain valid after password reset due to static cookie secret","id":"CVE-2026-40934","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":3,"n_references":1,"next":{"headline":"WWBN/AVideo has CAPTCHA Bypass via Attacker-Controlled Length Parameter and Missing Token Invalidation on Failure","id":"CVE-2026-40935"},"packages":[{"ecosystem":"PyPI","fixed":["2.18.0"],"introduced":["0"],"last_affected":[],"package":"jupyter-server","purl":null,"source":"GHSA-5mrq-x3x5-8v8f"},{"ecosystem":"PyPI","fixed":["2.18.0"],"introduced":["0"],"last_affected":[],"package":"jupyter-server","purl":"pkg:pypi/jupyter-server","source":"GHSA-5mrq-x3x5-8v8f"},{"ecosystem":"PyPI","fixed":["2.18.0"],"introduced":["0"],"last_affected":[],"package":"jupyter-server","purl":"pkg:pypi/jupyter-server","source":"PYSEC-2026-69"}],"prev":{"headline":"Flowise: Authenticated RCE Via MCP Adapters","id":"CVE-2026-40933"},"products":["jupyter_server"],"published":"2026-05-05","related":[{"cvss_score":9.3,"headline":"Jupyter Server: Stored XSS in `NbconvertFileHandler` / `NbconvertPostHandler` via missing `sandbox` CSP","id":"CVE-2026-44727","kev_date_added":null,"published":"2026-06-22"},{"cvss_score":7.6,"headline":"jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix","id":"CVE-2026-35397","kev_date_added":null,"published":"2026-05-05"},{"cvss_score":7.6,"headline":"jupyter-server CORS origin validation bypass via unanchored regex in allow_origin_pat","id":"CVE-2026-40110","kev_date_added":null,"published":"2026-05-05"},{"cvss_score":7.5,"headline":"Jupyter server on Windows discloses Windows user password hash","id":"CVE-2024-35178","kev_date_added":null,"published":"2024-06-06"},{"cvss_score":7.5,"headline":"Sensitive Auth \u0026 Cookie data stored in Jupyter server logs","id":"CVE-2022-24757","kev_date_added":null,"published":"2022-03-23"},{"cvss_score":7.1,"headline":"Known or guessable hidden files may be accessed in Jupyter Server","id":"CVE-2022-29241","kev_date_added":null,"published":"2022-06-14"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-05-07","vendors":["jupyter-server"]},"summary":"Attackers retain authenticated access after password resets because Jupyter Server fails to rotate the cookie signing secret, allowing session hijacking.","url":"https://insights.sbomify.com/CVE-2026-40934/"}