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TI-2026-26377 Aliases CVE-2026-34052GHSA-8mxq-7xr7-2fxj

LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)

Priority LOW 26CWE-401Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-401.

Summary

LTI JupyterHub Authenticator is a JupyterHub authenticator for LTI. Prior to version 1.6.3, the LTI 1.1 validator stores OAuth nonces in a class-level dictionary that grows without bounds. Nonces are added before signature validation, so an attacker with knowledge of a valid consumer key can send repeated requests with unique nonces to gradually exhaust server memory, causing a denial of service. This issue has been patched in version 1.6.3.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00342 27th percentileScored 2026-11-08
Fix Fixed ltiauthenticator (jupyterhub): 1.6.3jupyterhub-ltiauthenticator (PyPI): 1.6.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
jupyterhubltiauthenticatorbefore 1.6.31.6.3Patch availableCNA
—jupyterhub-ltiauthenticator (PyPI)before 1.6.31.6.3Patch availableGHSA-8mxq-7xr7-2fxj
  • ltiauthenticator Vendorjupyterhub Affected before 1.6.3 Fixed in 1.6.3 Patch available CNA
  • jupyterhub-ltiauthenticator (PyPI) Vendor— Affected before 1.6.3 Fixed in 1.6.3 Patch available GHSA-8mxq-7xr7-2fxj

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:jupyter:lti_jupyterhub_authenticator:*:*:*:*:*:*:*:*before 1.6.3Vulnerablejupyterlab
  • cpe:2.3:a:jupyter:lti_jupyterhub_authenticator:*:*:*:*:*:*:*:* Versions before 1.6.3 Vulnerable ·jupyterlab

Remediation

  • Fix · CNA ltiauthenticator (jupyterhub) Fixed in 1.6.3
  • Fix · GHSA-8mxq-7xr7-2fxj jupyterhub-ltiauthenticator (PyPI) Fixed in 1.6.3 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34052
  2. 2026-10-03 Alias added: GHSA-8mxq-7xr7-2fxj

References

Advisory 2

Other 2

  • TI-2025-23499 Jupyter Remote Desktop Proxy makes TigerVNC accessible via the network and not just via a UNIX socket as intended CVSS 4.0CRITICAL 9.0
  • TI-2023-10877 JupyterHub's LTI13Authenticator: JWT signature not validated CVSS 3.1CRITICAL 10.0
  • TI-2021-16545 Remote code execution in Binderhub CVSS 3.1CRITICAL 9.8
  • TI-2021-18033 Improper Access Control in jupyterhub-firstuseauthenticator CVSS 3.1CRITICAL 9.8
  • TI-2021-16546 Code injection in nbgitpuller CVSS 3.1CRITICAL 9.6
  • TI-2024-18755 Jupyter Server Proxy's Websocket Proxying does not require authentication CVSS 3.1CRITICAL 9.8
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences