{"id":"PYSEC-2026-2533","summary":"LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)","details":"## Summary\n\nThe 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.\n\n## Patches\n\n- upgrade jupyterhub-litauthenticator to 1.6.3","aliases":["CVE-2026-34052","GHSA-8mxq-7xr7-2fxj"],"modified":"2026-07-13T16:49:22.529213351Z","published":"2026-07-13T14:36:47.380994Z","references":[{"type":"WEB","url":"https://github.com/jupyterhub/ltiauthenticator/security/advisories/GHSA-8mxq-7xr7-2fxj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34052"},{"type":"PACKAGE","url":"https://github.com/jupyterhub/ltiauthenticator"},{"type":"WEB","url":"https://github.com/jupyterhub/ltiauthenticator/releases/tag/1.6.3"},{"type":"PACKAGE","url":"https://pypi.org/project/jupyterhub-ltiauthenticator"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-8mxq-7xr7-2fxj"}],"affected":[{"package":{"name":"jupyterhub-ltiauthenticator","ecosystem":"PyPI","purl":"pkg:pypi/jupyterhub-ltiauthenticator"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.3"}]}],"versions":["0.1","0.2","0.3","0.4.0","1.0.0","1.1.0","1.2.0","1.3.0","1.4.0","1.5.0","1.5.1","1.6.0","1.6.1","1.6.2"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/jupyterhub-ltiauthenticator/PYSEC-2026-2533.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}