Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Search

GHSA-5mrq-x3x5-8v8f

MediumCVSS 6.8 / 10
Published May 5, 2026·Last modified May 8, 2026
Affected Components(0)

No affected components available

Description

Summary

A persistent cookie secret vulnerability allows authenticated users to maintain indefinite access even after password changes.

The cookie secret used to sign authentication cookies is stored in a permanent file (~/.local/share/jupyter/runtime/jupyter_cookie_secret) that is never automatically rotated or cleared, allowing stolen or compromised cookies to remain valid indefinitely regardless of password resets.

PoC

  • Start a Jupyter server with password authentication: jupyter server password, jupyter server
  • Log in with the password and capture the authentication cookie (e.g., just login with a browser).
  • Change the password to revoke access: jupyter server password
  • Restart the server
  • Use the old stolen cookie => remains valid and provides full authenticated access.

Impact

  • All jupyter-server deployments using password authentication where security incidents may occur
  • Multi-user systems where one user's compromised session should be revocable by administrators
  • Shared or public-facing Jupyter servers where credential rotation is a security requirement
  • Any deployment where password changes are expected to revoke existing sessions

Patches

Jupyter Server 2.18+

Workaround

rm ~/.local/share/jupyter/runtime/jupyter_cookie_secret
# Then restart the server
Risk Scores
Base Score
6.8

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data.

Threat Intelligence
6.2

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.31%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard