Check Point Quantum EUVD-2026-35046

Exploitation requires that the target deployment uses IKEv1 (not IKEv2) for site-to-site VPN connectivity AND that the affected tunnels are configured with certificate-based authentication (not pre-shared keys), AND that the attacker holds an active man-in-the-middle position on the network path between the two VPN gateways during IKE negotiation/rekey. Limiting factors: high CVSS attack complexity (AC:H) reflects the MitM positioning requirement; remote-access VPNs (client-to-site) and IKEv2 tunnels are not described as in scope; deployments using PSK authentication on IKEv1 are also outside the certificate-validation code path. No user interaction is required (UI:N) and no authentication to the gateway is needed (PR:N).

The CVSS 3.1 base score of 7.4 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) reflects high impact to confidentiality and integrity but high attack complexity, because the adversary must already occupy a privileged network position between two VPN peers to perform the MitM - a non-trivial prerequisite typical of ISP-level, BGP-hijack, or compromised-transit scenarios. No EPSS score, KEV listing, or POC was provided, indicating no public exploit identified at time of analysis and no evidence of active exploitation. The realistic priority is moderate-to-high for organizations that still rely on IKEv1 with certificate-based site-to-site VPNs (notably traversing untrusted transit such as the public Internet or carrier networks), and lower for deployments that have already migrated to IKEv2 or use PSK-only IKEv1 over trusted transport. Note: the description references IKEv1 as 'deprecated,' so exposure depends on whether IKEv1 is actually configured - verify with Check Point's advisory before treating CVSS as a deployment-wide priority.

An attacker who has obtained an on-path position between two Check Point gateways - for example via BGP hijack, compromised ISP equipment, or rogue infrastructure on a shared transit segment - intercepts the IKEv1 negotiation between two corporate sites that authenticate using certificates. By presenting a crafted certificate that the flawed validation logic accepts despite not chaining to a legitimate trust anchor, the attacker completes the key exchange with each endpoint independently, then decrypts, inspects, and optionally rewrites IPsec-protected traffic flowing between the two sites. No public exploit code is identified at time of analysis.