CVE-2026-34052
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
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| jupyter | lti_jupyterhub_authenticator | to 1.6.3 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| 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. |
| 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. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
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.
How can this vulnerability impact me? :
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.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade the LTI JupyterHub Authenticator to version 1.6.3 or later, where the issue has been patched.