CVE-2026-59099 (GCVE-0-2026-59099)

Vulnerability from cvelistv5 – Published: 2026-07-02 19:42 – Updated: 2026-07-02 19:42 X_Open Source
VLAI?
Title
Apereo CAS 7.3.0 < 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure
Summary
Apereo CAS 7.3.0 before 8.0.0-RC6 contains a cryptographic vulnerability that allows remote unauthenticated attackers to recover plaintext conversation state by exploiting AES-GCM initialization vector reuse across the server lifetime. Attackers can collect multiple client-side webflow execution tokens from the unauthenticated login page and perform known-plaintext analysis to decrypt the webflow conversation state due to keystream reuse caused by a fixed all-zero IV paired with the same encryption key.
Severity ?
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
9.3 (Critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-323 - Reusing a Nonce, Key Pair in Encryption
Assigner
References
Impacted products
Vendor Product Version
apereo cas Affected: 7.3.0 , < 8.0.0-RC6 (custom)
Create a notification for this product.
Credits
George Chen
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "cas",
          "repo": "https://github.com/apereo/cas",
          "vendor": "apereo",
          "versions": [
            {
              "lessThan": "8.0.0-RC6",
              "status": "affected",
              "version": "7.3.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:apereo:central_authentication_service:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "8.0.0-RC6",
                  "versionStartIncluding": "7.3.0",
                  "vulnerable": true
                }
              ],
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "George Chen"
        }
      ],
      "datePublic": "2026-06-18T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Apereo CAS 7.3.0 before 8.0.0-RC6 contains a cryptographic vulnerability that allows remote unauthenticated attackers to recover plaintext conversation state by exploiting AES-GCM initialization vector reuse across the server lifetime. Attackers can collect multiple client-side webflow execution tokens from the unauthenticated login page and perform known-plaintext analysis to decrypt the webflow conversation state due to keystream reuse caused by a fixed all-zero IV paired with the same encryption key."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          },
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          "scenarios": [
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              "lang": "en",
              "value": "GENERAL"
            }
          ]
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        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
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              "value": "GENERAL"
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      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-323",
              "description": "Reusing a Nonce, Key Pair in Encryption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-02T19:42:51.897Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "Maintainer Advisory",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://apereo.github.io/2026/06/18/vuln/"
        },
        {
          "name": "Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/apereo/cas/releases/tag/v8.0.0-RC6"
        },
        {
          "name": "Researcher Disclosure",
          "tags": [
            "technical-description",
            "exploit"
          ],
          "url": "https://github.com/geo-chen/oss/blob/main/cas.md"
        },
        {
          "name": "Fix Commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/apereo/cas/commit/22c6f4adf738852782309b523b4e80371057f2d0"
        },
        {
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/apereo-cas-rc6-aes-gcm-nonce-reuse-information-disclosure"
        }
      ],
      "tags": [
        "x_open-source"
      ],
      "title": "Apereo CAS 7.3.0 \u003c 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-59099",
    "datePublished": "2026-07-02T19:42:51.897Z",
    "dateReserved": "2026-07-02T15:38:18.929Z",
    "dateUpdated": "2026-07-02T19:42:51.897Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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