Vulnerability · Published Apr 3, 2026 · Assigned by GitHub_M

CVE-2026-34052LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)

Medium 5.9

In plain English

A medium-severity memory leak in ltiauthenticator from jupyterhub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.3%top 72.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	jupyterhub-ltiauthenticator	1.6.3	GHSA-8mxq-7xr7-2fxj
PyPI	jupyterhub-ltiauthenticator	1.6.3	PYSEC-2026-2533

Affected products (as reported)

Vendor	Product	Versions
jupyterhub	ltiauthenticator	< 1.6.3

Weakness: CWE-401, CWE-770 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/jupyterhub/ltiauthenticator/security/advisories/GHSA-8mxq-7xr7-2fxj x_refsource_CONFIRM
https://github.com/jupyterhub/ltiauthenticator/releases/tag/1.6.3 x_refsource_MISC