CVE-2026-40934
jupyter-server authentication cookies remain valid after password reset due to static cookie secret
Vexday Risk Score
21Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 7.6EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
05 May 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
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
Affected products
jupyter-server · jupyter_serverWant to know if your infrastructure is exposed to this?
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