CVE-2026-34052
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedLTI 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe LTI JupyterHub Authenticator's LTI 1.1 validator stores OAuth nonces in an unbounded class-level dictionary. An attacker with a valid consumer key can send repeated requests with unique nonces, causing the dictionary to grow indefinitely and exhaust server memory, resulting in denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.6.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed version of Jupyter LTI JupyterHub AuthenticatorRun the package manager command to display the installed version (for example: pip show lti-jupyterhub-authenticator or conda list lti-jupyterhub-authenticator)Affected if The version listed is below 1.6.3
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Determine if LTI 1.1 authentication is in useReview the JupyterHub configuration for LTI authenticator settings, specifically looking for LTI 1.1 consumer keys and the authenticator class being usedAffected if LTI 1.1 authentication is configured and active in the JupyterHub deployment
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Inspect the nonce storage mechanismExamine the source code or runtime behavior of the LTI 1.1 validator to confirm whether nonces are stored in a class-level dictionary that persists across requestsAffected if The nonce storage uses a growing in-memory dictionary without expiration or size limits
You are affected if running a version of Jupyter LTI JupyterHub Authenticator below 1.6.3 with LTI 1.1 authentication enabled, where the nonce storage mechanism allows unbounded memory growth.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.6.3
Upgrade to version 1.6.3 or later. Additionally, consider rate limiting and monitoring memory usage on servers running the authenticator to detect potential exploitation.
1.6.3
- Check the currently installed version of lti-jupyterhub-authenticator using pip show or pip list
- Upgrade the package to version 1.6.3 or later using: pip install --upgrade lti-jupyterhub-authenticator>=1.6.3
- Verify the upgrade was successful by checking the installed version: pip show lti-jupyterhub-authenticator
- Restart the JupyterHub service to ensure the new version is loaded
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34052 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-34052 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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