CVE-2026-34052
Received Received - Intake
Denial of Service via OAuth Nonce Exhaustion in LTI JupyterHub Authenticator

Publication date: 2026-04-03

Last updated on: 2026-04-13

Assigner: GitHub, Inc.

Description
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.
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Meta Information
Published
2026-04-03
Last Modified
2026-04-13
Generated
2026-06-19
AI Q&A
2026-04-04
EPSS Evaluated
2026-06-18
NVD
CVE-2026-34052
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
jupyter lti_jupyterhub_authenticator to 1.6.3 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
CWE-401 The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
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Executive Summary

The vulnerability exists in the LTI JupyterHub Authenticator prior to version 1.6.3. Specifically, the LTI 1.1 validator stores OAuth nonces in a class-level dictionary that grows without limits. Since nonces are added before signature validation, an attacker who knows a valid consumer key can send many requests with unique nonces. This causes the dictionary to grow continuously, eventually exhausting the server's memory and leading to a denial of service.

Impact Analysis

This vulnerability can impact you by causing a denial of service (DoS) on the server running the LTI JupyterHub Authenticator. An attacker can exploit the unlimited growth of stored nonces to consume server memory, potentially making the service unavailable to legitimate users.

Mitigation Strategies

To mitigate this vulnerability, upgrade the LTI JupyterHub Authenticator to version 1.6.3 or later, where the issue has been patched.

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