{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:composer/bookstackapp/bookstack",
          "product": "bookstack",
          "vendor": "bookstackapp",
          "versions": [
            {
              "lessThan": "26.05.4",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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                  "criteria": "cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "26.05.4",
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Submersion.ai Security Research Team"
        }
      ],
      "datePublic": "2026-08-22T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests."
        }
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          "cvssV4_0": {
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            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
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            "baseScore": 8.8,
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            "confidentialityImpact": "HIGH",
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            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-434",
              "description": "Unrestricted Upload of File with Dangerous Type",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-29T13:47:53.312Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "Patch Commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/BookStackApp/BookStack/commit/e210cc32e4cbb1efeae5c5c9d0fef8e3c6a752e6"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/BookStackApp/BookStack"
        },
        {
          "name": "VulnCheck Advisory: BookStack before 26.05.4 Remote Code Execution via Book Cover",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/bookstack-before-26.05.4-remote-code-execution-via-book-cover"
        }
      ],
      "title": "BookStack before 26.05.4 Remote Code Execution via Book Cover",
      "x_generator": {
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      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-82450",
    "datePublished": "2026-08-29T13:47:53.312Z",
    "dateReserved": "2026-08-29T13:22:57.885Z",
    "dateUpdated": "2026-08-29T13:47:53.312Z",
    "state": "PUBLISHED"
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  "dataVersion": "5.2"
}