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MEDIUM severity

CVE-2026-34052 — jupyterhub-ltiauthenticat…

MEDIUM

CVE-2026-34052 is a medium-severity (CVSS 5.9) CWE-401 vulnerability in jupyterhub-ltiauthenticator. A fix is available for jupyterhub-ltiauthenticator — see the affected versions and patch details below.

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

Also known asGHSA-8mxq-7xr7-2fxjPYSEC-2026-2533
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-34052.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs28th percentile — riskier than 28% of all scored CVEsHighest risk
0.00%0.30%0.61%0.91%0.1%0.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐍jupyterhub-ltiauthenticator

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIjupyterhub-ltiauthenticatorall versions1.6.3pip install --upgrade 'jupyterhub-ltiauthenticator==1.6.3'

Affected Products

1 product · 1 configurations
Application
lti jupyterhub authenticatorjupyter
< 1.6.3
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jupyterhub-ltiauthenticator, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update jupyterhub-ltiauthenticator to 1.6.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34052 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2026-34052: jupyterhub DoS — Fixed in 1.6.3