CVE-2026-69088: Grav Incomplete Callable Validation Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7pgq-cr25-xvc8",
  "modified" : "2026-09-17T17:16:39Z",
  "published" : "2026-09-17T17:16:39Z",
  "aliases" : [ "CVE-2026-69088" ],
  "summary" : "Grav: Incomplete callable validation in blueprint dynamic fields allows arbitrary static method invocation and file disclosure",
  "details" : "### Summary\nGrav CMS's blueprint dynamic-field callable guard can be bypassed with a fully-qualified `Class::method` string, letting an account with only page-editing rights (`admin.pages`, not super-admin) plant a directive in a page's form-field frontmatter that invokes an arbitrary public static PHP method with attacker-controlled arguments. Using built-in gadget methods this yields, at minimum, arbitrary reading of any server-readable file (disclosed to anonymous visitors of the crafted page) and arbitrary creation/copying of files and directories under the web-server account.\n\n### Details\n`Blueprint::isSafeDynamicCall()` (`system/src/Grav/Common/Data/Blueprint.php`, method around line 488) is meant to block dangerous callables named in a blueprint's dynamic-field directives (`data-*@`). It only consults its dangerous-name denylist when the callable string does **not** contain `::`:\n```php\nif (is_string($function) && !str_contains($function, '::') && Utils::isDangerousFunction($function)) {\n    return false;\n}\n```\nAny callable string containing `::` — i.e. every `Class::method` static call — skips the check entirely and is passed to `call_user_func_array()` at `Blueprint::dynamicData()` (`Blueprint.php`, around line 461) and `FlexDirectory::dynamicDataField()` (`system/src/Grav/Framework/Flex/FlexDirectory.php`, around line 937). There is no allowlist restricting which classes or methods may be invoked this way; only the call's *arguments* are (separately) scanned for smuggled dangerous callables, never the target itself.\n\n`Utils::isDangerousFunction()` (`system/src/Grav/Common/Utils.php`) classifies any string containing a colon (`str_contains($name, \":\")`) or a namespace backslash as dangerous — so a qualified `Class::method` string would be rejected *if* it ever reached this function. The `!str_contains($function, '::')` condition in `isSafeDynamicCall()` ensures it never does, which is what leaves qualified static calls entirely unscreened. (Whether the exemption was intended to admit legitimate `Class::method` option-providers is a plausible reading of the surrounding code, but the intent is not established here.)\n\nThis is an incomplete fix of two recently published advisories — one addressing page editors executing hidden callables via form-field settings, the other extending the same guard to Flex directories. The guard those fixes introduced never covered qualified static calls. Grav's own permission model separates page-content code execution into a distinct, higher privilege (`admin.pages_twig`) from plain page editing (`admin.pages`), so invoking arbitrary methods from an `admin.pages`-authored page is a genuine trust-boundary bypass, not editor capability by design.\n\n### PoC\nTested on Grav `develop` at commit `db8c1fc` (which self-reports version 2.0.11) with the admin and form plugins, using an account granted only `admin.login` + `admin.pages` (page editor, not super-admin). The same guard is present in every current release from 2.0.7 through 2.0.10. Base URL shown as `https://grav.example`.\n\n**A. Arbitrary file read (confidentiality)**\n\n1. Log in to `/admin` as the page-editor account (GET `/admin` for the login nonce, then POST `task=login`).\n2. Save a page via the standard admin endpoint, `POST /admin/pages/<route>` with the session cookie, the admin nonce, and `data[frontmatter]` containing a form field with a `download` gadget directive:\n    ```yaml\n    forms:\n      x:\n        fields:\n          y:\n            type: text\n            data-opts@:\n              - 'Grav\\Common\\Utils::download'\n              - '/etc/passwd'\n              - false\n              - 0\n              - 1024\n              - mime: 'text/plain'\n    ```\n   The server returns `HTTP 200` and accepts the save — the `data-opts@` directive is not rejected.\n3. As an unauthenticated visitor (no cookies), request the saved page, e.g. `GET /<route>` (use a fresh query string to avoid a cached copy; immediately after saving, a first request may `404` while the flat-file page index catches up — retry moments later). The response is `HTTP 200` with the raw contents of `/etc/passwd` in the body (`root:x:0:0:...`). Pointing the path at `user/accounts/<name>.yaml` instead returns that account file, including its `hashed_password:` bcrypt line — i.e. an anonymous visitor obtains a stored administrator's password hash.\n\n**B. Arbitrary file/directory write (integrity) — verified**\n\nUsing the same mechanism with `Grav\\Common\\Filesystem\\Folder::copy` (a public static method taking source and destination paths), a page editor caused the server to copy an existing page directory to an attacker-chosen new path under `user/pages/`; the newly created page then rendered its (attacker-controlled) content at the new route over plain HTTP. This demonstrates attacker-controlled creation of files/directories anywhere the web-server account can write. `Folder::move` and `Folder::delete` are equally reachable (their destructive nature was not exercised).\n\n### Impact\nA page editor (an `admin.pages`-only account, **not** super-admin) can, through a page they author:\n\n- **Read any server-readable file**, disclosed to any anonymous, unauthenticated visitor of the crafted page — including `user/accounts/*.yaml`, which stores account metadata and bcrypt password hashes. An attacker may attempt offline cracking of a disclosed hash; recovery of a weak or reused administrator password could lead to full admin-panel compromise. Other secrets on disk (site/plugin config, environment files) are equally exposed.\n- **Create or overwrite files and directories** under the web-server account (demonstrated via `Folder::copy`), with `Folder::move`/`Folder::delete` additionally reachable for destructive tampering.\n\nBecause the guard permits *any* public static method, the reachable impact is bounded only by the gadget surface of the loaded codebase, not by this report's demonstrated cases.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "getgrav/grav"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.7"
      }, {
        "fixed" : "2.0.11"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.0.10"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/getgrav/grav/security/advisories/GHSA-7pgq-cr25-xvc8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-69088"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/getgrav/grav"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/grav-cms-through-arbitrary-method-invocation-via-blueprint"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-470", "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-17T17:16:39Z",
    "nvd_published_at" : null
  }
}