CVE-2026-34052
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
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.
- Record
CVE-2026-34052- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401, CWE-770
- Updated
- 2026-11-02
EUVDEUVD-2026-18893
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.
- Record
EUVD-2026-18893- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8mxq-7xr7-2fxj
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
Summary
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.
Patches
- upgrade jupyterhub-litauthenticator to 1.6.3
- Record
GHSA-8mxq-7xr7-2fxj- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401, CWE-770
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-34052- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401, CWE-770
- Updated
- 2026-11-02
OSV
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
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.
- Record
CVE-2026-34052- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401, CWE-770
- Updated
- 2026-11-02
OSVGHSA-8mxq-7xr7-2fxj
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
Summary
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.
Patches
- upgrade jupyterhub-litauthenticator to 1.6.3
- Record
GHSA-8mxq-7xr7-2fxj- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401, CWE-770
- Updated
- 2026-11-02
OSVPYSEC-2026-2533
LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)
Summary
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.
Patches
- upgrade jupyterhub-litauthenticator to 1.6.3
- Record
PYSEC-2026-2533- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
jupyterhub-ltiauthenticatorPyPI |
through 1.6.2 | 1.6.3 |
jupyterhub-ltiauthenticatorPyPI |
before 1.6.3, plus listed versions 0.10.20.30.4.01.0.0 Show 9 moreShow less1.1.01.2.01.3.01.4.01.5.01.5.11.6.01.6.11.6.2 |
1.6.3 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-34052 is a medium vulnerability (CVSS 5.9) in Jupyter Lti Jupyterhub Authenticator, published April 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 27th percentile. Fixed in jupyterhub-ltiauthenticator 1.6.3.
References
github.com/jupyterhub/ltiauthenticator/security/advisories/GHSA-8mxq-7xr7-2fxj
nvd.nist.gov/vuln/detail/CVE-2026-34052
pypi.org/project/jupyterhub-ltiauthenticator