Medium severity · published Apr 3, 2026
CVE-2026-34052
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
5.9
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 26% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LT
ltiauthenticator · jupyterhub
< 1.6.3 · source: vendor
LJ
Lti Jupyterhub Authenticator · Jupyter
before 1.6.3 · source: NVD