b2evolution CMS 6.7.8 through 7.2.5 Object Injection via Negative Integer Array Key

{
  "id": "33890cab5c78415a0d0c8a4f3491d2748819692b3ccec8bca9c182c0c93e5fe3",
  "url": "https://osv.dev/vulnerability/CVE-2026-76834",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "b2evolution CMS 6.7.8 through 7.2.5 Object Injection via Negative Integer Array Key",
    "summary": "b2evolution CMS versions 6.7.8 through 7.2.5 contain an incomplete fix for CVE-2016-8901 where the serialized-array object check in param_check_serialized_array() fails to reject payloads with negative integer array keys. Unauthenticated attackers can submit crafted serialized PHP objects via POST requests to htsrv/call_plugin.php that bypass validation and reach unserialize(), instantiating arbitrary PHP objects with attacker-chosen properties that may enable code execution if suitable POP gadget chains exist.",
    "evidence": "osv:CVE-2026-76834",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-76834",
      "aliases": [
        "CVE-2026-76834"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/b2evolution/b2evolution",
              "type": "GIT",
              "events": [
                {
                  "introduced": "baf4c9d1245b0149dca900b50e812b059c011b31"
                },
                {
                  "fixed": "25c21cf9cc4261324001f9039509710b37ee2c4d"
                },
                {
                  "fixed": "999b5ad1d59760d7e450ceb541f55432fc74cd27"
                },
                {
                  "fixed": "335abf09bcea61717bd00bc1e3889f8100ebd1bb"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "6.7.8"
                      },
                      {
                        "last_affected": "7.2.5"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "25c21cf9cc4261324001f9039509710b37ee2c4d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "999b5ad1d59760d7e450ceb541f55432fc74cd27"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "335abf09bcea61717bd00bc1e3889f8100ebd1bb"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-76834.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.332139118Z",
      "provider": "osv",
      "references": [
        "https://b2evolution.net/news/2022/03/26/2022-update-eol",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/76xxx/CVE-2026-76834.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-76834",
        "https://www.vulncheck.com/advisories/b2evolution-cms-6.7.8-through-7.2.5-object-injection-via-negative-integer-array-key",
        "https://github.com/b2evolution/b2evolution/commit/25c21cf9cc4261324001f9039509710b37ee2c4d",
        "https://github.com/b2evolution/b2evolution/commit/335abf09bcea61717bd00bc1e3889f8100ebd1bb",
        "https://github.com/b2evolution/b2evolution/commit/999b5ad1d59760d7e450ceb541f55432fc74cd27",
        "https://github.com/b2evolution/b2evolution",
        "https://gist.github.com/axg11/3e29501c33f6e1e05ac2a00107afd64e",
        "https://github.com/b2evolution/b2evolution/blob/7.2.5/htsrv/call_plugin.php#L49",
        "https://github.com/b2evolution/b2evolution/blob/7.2.5/inc/_core/_param.funcs.php#L2860"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-502"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/76xxx/CVE-2026-76834.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-76834",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517512,
  "published_at": "2026-09-17T15:16:50.748+00:00"
}