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CVE-2026-40934— jupyter-server authentication cookies remain valid after password reset due to static cookie secret

Quick assessment

Affected
jupyter-server jupyter_server
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Jupyter Server是Jupyter组织的一款用于为Jupyter Web应用提供后端服务的应用软件。 Jupyter Server 2.17.0及之前版本存在代码问题漏洞，该漏洞源于用于签名认证cookie的密钥持久化到静态文件且用户更改密码后不轮换，可能导致攻击者通过捕获的会话cookie在密码更改后仍保持完全认证访问。

AI Predicted 8.1 Difficulty: Easy EPSS 0.38% · P30

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
jupyter-server jupyter_server < 2.18.0 affected
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I. Basic Information for CVE-2026-40934

Vulnerability Information
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Vulnerability Title
jupyter-server authentication cookies remain valid after password reset due to static cookie secret
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
不充分的会话过期机制
Source: CVE Program / CVE List V5
Vulnerability Title
Jupyter Server 代码问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Jupyter Server是Jupyter组织的一款用于为Jupyter Web应用提供后端服务的应用软件。 Jupyter Server 2.17.0及之前版本存在代码问题漏洞，该漏洞源于用于签名认证cookie的密钥持久化到静态文件且用户更改密码后不轮换，可能导致攻击者通过捕获的会话cookie在密码更改后仍保持完全认证访问。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
jupyter-server jupyter_server < 2.18.0 -

II. Public POCs for CVE-2026-40934

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III. Intelligence Information for CVE-2026-40934

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Vendor Advisories for CVE-2026-40934 (1)

Same Patch Batch · jupyter-server · 2026-05-05 · 4 CVEs total

CVE-2026-35397 7.6 HIGH jupyter-server path traversal allows access to sibling directories sharing root_dir name p
CVE-2025-61669 jupyter_server next parameter open redirect can redirect users to external domains
CVE-2026-40110 jupyter-server CORS origin validation bypass via unanchored regex in allow_origin_pat

IV. Related Vulnerabilities

Same product: jupyter_server
Same vendor: jupyter-server
Same weakness: CWE-613

V. Comments for CVE-2026-40934

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