CVE-2026-9891

// Conceptual Proof of Concept for CVE-2026-9891 // This demonstrates the logic of a Use-After-Free in Chrome Extensions. // Note: Actual exploitation requires precise memory layout control. function exploit_uaf() { // Step 1: Create a vulnerable object within the Extension context let vuln_object = new chrome.extension.VulnerableObject(); // Step 2: Trigger the free operation on the object // Simulating a scenario where the object is deallocated vuln_object.destroy(); vuln_object = null; // Step 3: Force Garbage Collection (implementation dependent) if (window.gc) { window.gc(); } // Step 4: Reuse the freed memory (Use-After-Free) // Attempting to access the memory where vuln_object resided // If successful, this allows corrupting the vtable or executing arbitrary code console.log("Attempting to reallocate memory for exploitation..."); // In a real exploit, this memory would be sprayed with controlled data // to hijack control flow and escape the sandbox. } exploit_uaf();

{"cve": {"id": "CVE-2026-9891", "sourceIdentifier": "[email protected]", "published": "2026-05-28T23:16:47.083", "lastModified": "2026-05-29T17:15:18.660", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Use after free in Extensions in Google Chrome prior to 148.0.7778.216 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted Chrome Extension. (Chromium security severity: Critical)"}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H", "baseScore": 9.0, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.2, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-416"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:*", "versionEndExcluding": "148.0.7778.216", "matchCriteriaId": "E59192D9-BF13-4B43-B69F-869A6BF83955"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*", "matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:*", "versionEndExcluding": "148.0.7778.215", "matchCriteriaId": "875ACED4-0D6D-4BAA-8FAF-F13B5FEDF09A"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:o:apple:macos:-:*:*:*:*:*:*:*", "matchCriteriaId": "387021A0-AF36-463C-A605-32EA7DAC172E"}, {"vulnerable": false, "criteria": "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*", "matchCriteriaId": "703AF700-7A70-47E2-BC3A-7FD03B3CA9C1"}]}]}], "references": [{"url": "https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html", "source": "[email protected]", "tags": ["Vendor Advisory", "Release Notes"]}, {"url": "https://issues.chromium.org/issues/513508128", "source": "[email protected]", "tags": ["Permissions Required"]}]}}