CVE-2026-34052Network attack vector

Service interruption via pre-validation nonce accumulation

Published Apr 3, 2026 · Updated Apr 3, 2026

Resource exhaustion in LTI JupyterHub Authenticator before 1.6.3 allows remote attackers to interrupt service through LTI 1.1 requests. The LTI 1.1 validator inserts each OAuth nonce into a class-level dictionary before checking the request signature, and the dictionary has no size bound or eviction path. Knowledge of a valid consumer key is required; repeated requests carrying unique nonces steadily consume server memory until the JupyterHub service becomes unavailable.

CVSS severity5.9
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in LTI JupyterHub Authenticator before 1.6.3 allows remote attackers to interrupt service through LTI 1.1 requests. The LTI 1.1 validator inserts each OAuth nonce into a class-level dictionary before checking the request signature, and the dictionary has no size bound or eviction path. Knowledge of a valid consumer key is required; repeated requests carrying unique nonces steadily consume server memory until the JupyterHub service becomes unavailable.

The record

CVE
CVE-2026-34052
Published
Apr 3, 2026
Updated
Apr 3, 2026
Vendor
Project Jupyter
Product
LTI JupyterHub Authenticator
Classifications
CWE-770, CWE-401, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.6.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Project Jupyter · LTI JupyterHub Authenticatorversion=< 1.6.3

Published CVSS scores

5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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