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ImpressCMS Authenticated RCE via PHP Custom Tag eval()

Type: advisorySources: OSV

ImpressCMS contains an authenticated remote code execution vulnerability in the custom tag module that allows authenticated administrators to execute arbitrary PHP code by storing a malicious payload in a custom tag with PHP type enabled. The application decodes HTML-encoded content via undoHtmlSpecialChars() before passing it to eval() in the renderWithPhp() method, bypassing HTML Purifier sanitization, and the payload is triggered on every frontend page load through the preload event system.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-73679
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 16:39 UTC · Revision 1

Source evidence

ImpressCMS Authenticated RCE via PHP Custom Tag eval()

core-osv · Original source

Published 14 Aug 2026, 19:03 UTC

ImpressCMS contains an authenticated remote code execution vulnerability in the custom tag module that allows authenticated administrators to execute arbitrary PHP code by storing a malicious payload in a custom tag with PHP type enabled. The application decodes HTML-encoded content via undoHtmlSpecialChars() before passing it to eval() in the renderWithPhp() method, bypassing HTML Purifier sanitization, and the payload is triggered on every frontend page load through the preload event system.

osv:CVE-2026-73679
Complete source record
{
  "id": "f92490b6e341e38a063ae300be5f609a58bf740e7761ae67e18f47304c525672",
  "url": "https://osv.dev/vulnerability/CVE-2026-73679",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ImpressCMS Authenticated RCE via PHP Custom Tag eval()",
    "summary": "ImpressCMS contains an authenticated remote code execution vulnerability in the custom tag module that allows authenticated administrators to execute arbitrary PHP code by storing a malicious payload in a custom tag with PHP type enabled. The application decodes HTML-encoded content via undoHtmlSpecialChars() before passing it to eval() in the renderWithPhp() method, bypassing HTML Purifier sanitization, and the payload is triggered on every frontend page load through the preload event system.",
    "evidence": "osv:CVE-2026-73679",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-73679",
      "aliases": [
        "CVE-2026-73679"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/impresscms/impresscms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "5fbdbc9e44e0b60fd9f2afbe1f8ca2cf69ee9621"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.0.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.0.3",
            "v2.0.3_beta",
            "v2.0.2",
            "v2.0.2_rc",
            "v2.0.2_beta",
            "v2.0.1",
            "v2.0.0",
            "v2.0.0_rc",
            "v2.0.0_beta_3",
            "v2.0.0_beta_1",
            "v1.5.0-rc",
            "v1.4.4",
            "v1.5.0-beta",
            "v1.4.3",
            "v1.4.3-rc2",
            "v1.4.3-rc",
            "v1.4.2_bis",
            "v1.4.2",
            "v1.4.2_rc",
            "v1.4.0",
            "v1.4.0-rc",
            "v1.4.0-beta",
            "v1.4.0-alpha.2",
            "v1.4.0-alpha",
            "v1.3.11",
            "v1.3.11-rc2",
            "v1.3.11-rc",
            "v1.3.11-beta2",
            "v1.3.11-beta",
            "v1.3.10",
            "1.3.10-beta",
            "1.3.9",
            "1.3.9_rc",
            "v1.3.8",
            "1.3.8",
            "impresscms_1.3.4",
            "impresscms_1.3.3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73679.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.509754775Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73679.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-73679",
        "https://www.vulncheck.com/advisories/impresscms-authenticated-rce-via-php-custom-tag-eval",
        "https://github.com/ImpressCMS/impresscms",
        "https://github.com/DevVaibhav07/VULN-POC/blob/main/ImpressCMSRCCE.md"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-94"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73679.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-73679",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504793,
  "published_at": "2026-08-14T19:03:24.913+00:00"
}