Control panel only API response emulation replaces "securityKey" and reaches server RCE

{
  "id": "e424991af44fe9872d4419b0bb65167052da5fdd947f2b508104a2a6f0da4821",
  "url": "https://osv.dev/vulnerability/CVE-2026-115935",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Control panel only API response emulation replaces \"securityKey\" and reaches server RCE",
    "summary": "The app/process-api-response-headers action accepts fake Craft API response headers from any authenticated control panel user. A non-admin user with only accessCp can place newline characters in X-Craft-Plugin-Licenses. Craft passes this value to its .env writer without removing the newlines. This lets the user insert a new attacker-known CRAFT_SECURITY_KEY into .env. After Craft loads that key, the user can forge a signed login redirect containing a Twig system() callback. This is different from the previous report. That report reads the existing key through a Twig sandbox bypass. This report replaces the key through fake API headers and CRLF injection. Fixing either source does not fix the other.",
    "evidence": "osv:CVE-2026-115935",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-115935",
      "aliases": [
        "CVE-2026-115935",
        "GHSA-9hp6-3565-gvh5"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/craftcms/cms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f6a8fb685d44e387435825e3a96809eeda4973a6"
                },
                {
                  "fixed": "a29fe6f87bbba6453e9d488ab8a8145a8a9e4f96"
                },
                {
                  "introduced": "982efcd14d7e93a1a54f0905b61f242de6b53d8a"
                },
                {
                  "fixed": "2ad6097618e4e7913f7f242d112a6e6e67cf2e8b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "5.0.0"
                      },
                      {
                        "fixed": "5.11.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "4.0.0"
                      },
                      {
                        "fixed": "4.18.9"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a29fe6f87bbba6453e9d488ab8a8145a8a9e4f96"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "5.11.2"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-115935.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.508357520Z",
      "provider": "osv",
      "references": [
        "https://packagist.org",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-115935.json",
        "https://github.com/craftcms/cms/releases/tag/5.11.2",
        "https://github.com/craftcms/cms/security/advisories/GHSA-9hp6-3565-gvh5",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-115935",
        "https://www.hckrt.com/hacktivity/HCKRT-WM3VSE",
        "https://github.com/craftcms/cms"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-94"
        ],
        "cna_assigner": "Hackrate",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-115935.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-115935",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 516739,
  "published_at": "2026-10-23T21:40:57.592+00:00"
}