PYSEC-2026-2533

Vulnerability from pysec - Published: 2026-07-13 14:36 - Updated: 2026-07-13 16:04
VLAI
Details

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
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Impacted products
Name purl
jupyterhub-ltiauthenticator pkg:pypi/jupyterhub-ltiauthenticator
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "jupyterhub-ltiauthenticator",
        "purl": "pkg:pypi/jupyterhub-ltiauthenticator"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.6.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34052",
    "GHSA-8mxq-7xr7-2fxj"
  ],
  "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",
  "id": "PYSEC-2026-2533",
  "modified": "2026-07-13T16:04:22.882070Z",
  "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"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "LTI JupyterHub Authenticator: Unbounded Memory Growth via Nonce Storage (Denial of Service)"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.