CVE-2026-40934Jupyter Server is the backend for Jupyter web applications.
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 6.8 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
- Weakness (CWE)
- CWE-613
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jul 25, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
jupyter jupyter_server jupyter:jupyter_server | before 2.18.0 | NVD |
References
- https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-5mrq-x3x5-8v8fexploit, mitigation, vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.