CVE-2026-45120 (GCVE-0-2026-45120)
Vulnerability from cvelistv5
Published
2026-08-18 15:52
Modified
2026-08-18 17:46
CWE
  • CWE-639 - Authorization Bypass Through User-Controlled Key
Summary
MyBB is free and open source forum software. Prior to 1.8.40, the calendar module does not verify private event status consistently, allowing users with viewing and moderation permissions to access and moderate private events. The private-event check used by get_events() in inc/functions_calendar.php and the event action is missing from the remaining calendar.php actions, despite the limited-access behavior described in inc/languages/english/calendar.lang.php. This issue is fixed in version 1.8.40.
Impacted products
Vendor Product Version
mybb mybb Version: < 1.8.40
Create a notification for this product.
Show details on NVD website


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        "metrics": [
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              "content": {
                "id": "CVE-2026-45120",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-18T17:19:13.557606Z",
                "version": "2.0.3"
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        "providerMetadata": {
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
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        "title": "CISA ADP Vulnrichment"
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        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
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      "problemTypes": [
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        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      "references": [
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          "name": "https://github.com/mybb/mybb/security/advisories/GHSA-c2hm-g9w6-pv6x",
          "tags": [
            "x_refsource_CONFIRM"
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          "url": "https://github.com/mybb/mybb/security/advisories/GHSA-c2hm-g9w6-pv6x"
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        {
          "name": "https://github.com/mybb/mybb/commit/c077e6c29755187c4df78a1e674dd61bc55701b3",
          "tags": [
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          "url": "https://github.com/mybb/mybb/commit/c077e6c29755187c4df78a1e674dd61bc55701b3"
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        "discovery": "UNKNOWN"
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    "datePublished": "2026-08-18T15:52:03.093Z",
    "dateReserved": "2026-05-08T20:08:17.208Z",
    "dateUpdated": "2026-08-18T17:46:20.052Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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