FKIE_CVE-2026-26717

Vulnerability from fkie_nvd - Published: 2026-02-25 17:25 - Updated: 2026-06-17 10:26
Severity
4.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Summary
An issue in OpenFUN Richie (LMS) in src/richie/apps/courses/api.py. The application used the non-constant time == operator for HMAC signature verification in the sync_course_run_from_request function. This allows remote attackers to forge valid signatures and bypass authentication by measuring response time discrepancies
References
cve@mitre.orghttps://github.com/Rickidevs/CVE-2026-26717
cve@mitre.orghttps://github.com/openfun/richie/commit/a1b5bbda3403d7debb466c303a32852925fcba5f
cve@mitre.orghttps://medium.com/@ordogh/cve-2026-26717-hmac-timing-attack-in-openfun-richie-lms-f04377efe83d?postPublishedType=repub
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue in OpenFUN Richie (LMS) in src/richie/apps/courses/api.py. The application used the non-constant time == operator for HMAC signature verification in the sync_course_run_from_request function. This allows remote attackers to forge valid signatures and bypass authentication by measuring response time discrepancies"
    },
    {
      "lang": "es",
      "value": "Un problema en OpenFUN Richie (LMS) en src/richie/apps/courses/api.py. La aplicaci\u00f3n utiliz\u00f3 el operador == de tiempo no constante para la verificaci\u00f3n de firmas HMAC en la funci\u00f3n sync_course_run_from_request. Esto permite a atacantes remotos forjar firmas v\u00e1lidas y eludir la autenticaci\u00f3n midiendo las discrepancias en el tiempo de respuesta."
    }
  ],
  "id": "CVE-2026-26717",
  "lastModified": "2026-06-17T10:26:15.757",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 2.5,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-26717",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-02-26T19:10:20.591862Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-02-25T17:25:39.293",
  "references": [
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/Rickidevs/CVE-2026-26717"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/openfun/richie/commit/a1b5bbda3403d7debb466c303a32852925fcba5f"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://medium.com/@ordogh/cve-2026-26717-hmac-timing-attack-in-openfun-richie-lms-f04377efe83d?postPublishedType=repub"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-208"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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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.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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Detection rules are retrieved from Rulezet.