External risk intelligence

Check Point Security Gateway IKEv1 Authentication Bypass Vulnerability.

CVE advisoryKnown Exploit

CVE-2026-50751

A logic flow weakness in certificate validation within a deprecated VPN protocol allows unauthenticated remote attackers to bypass user authentication and establish unauthorized VPN connections without a password. The relevance of this vulnerability depends on the use of this specific deprecated protocol for remote or

5Halo Surface Signal

Authentication Bypass

Checkpoint Gaia Os

r80.40 to before r81.20r81.20r82

External exposure likelihood

Halo Surface Signal score for CVE-2026-50751

The vulnerability affects a remote access VPN gateway. These devices are designed to be public-facing to facilitate remote connectivity for users, making them internet-accessible by default in normal deployment configurations.

PCI scan relevance

PCI Relevance for CVE-2026-50751

Yes

CVE-2026-50751 — Halo PCI Relevance: Yes. Under typical PCI ASV external scan criteria, this issue may be flagged for scan prioritization.

This vulnerability allows unauthenticated remote attackers to bypass VPN authentication, posing a direct risk to network access controls required by PCI DSS.

Scan-prioritization guidance only—not a PCI DSS certification or ASV attestation.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

Horizon Alert

Summary of the vulnerability and why it matters

A security vulnerability has been identified in a deprecated VPN protocol used for remote and mobile access. This flaw could allow an unauthorized external attacker to bypass authentication and gain access to the network without a valid password. The primary concern is to confirm if our environment utilizes this specific deprecated protocol and is therefore exposed.

  • Unauthenticated remote access bypass.
  • Affects legacy VPN access methods.
  • Confirm relevance and exposure.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker could exploit a weakness in how deprecated VPN protocols handle security keys to bypass login requirements. This allows them to establish a remote connection to the network without needing a password.

  • No user authentication needed.
  • Bypass deprecated key exchange.
  • Gain unauthorized network access.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an unauthenticated remote attacker to bypass user authentication and establish a remote access VPN connection without a valid password, provided the deprecated IKEv1 protocol is in use.

  • Unauthorized VPN access.
  • Bypass of user authentication.
  • Establish remote VPN connection.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical vulnerability, affecting remote access VPN connections, likely falls under the purview of network or security teams responsible for the VPN infrastructure. The initial step should involve identifying all instances of the affected Check Point Security Gateway, assessing their exposure and criticality, and then coordinating remediation with the vendor and relevant system owners.

  • Network and Security teams own this issue.
  • Verify VPN gateway reachability and exposure.
  • Plan vendor-coordinated remediation.

DETECT

How to detect the assets.

Nmap can perform an inventory check of exposed Check Point gateways by scanning UDP port 500 and UDP port 4500 for IKE/ISAKMP services. Utilizing the safe ike-version NSE script allows operators to determine if the deprecated IKEv1 protocol is enabled, though Nmap cannot verify if the specific certificate validation logic flaw is present or patched.

bash
nmap -Pn -sU -p 500,4500 --script ike-version TARGET

Frequently asked questions

What is the Check Point Security Gateway?

The Check Point Security Gateway acts as a central defensive hub for an organization's network perimeter. It manages traffic between different network segments and provides secure remote access capabilities, such as VPNs, allowing employees to connect safely to internal resources while working away from the office.

What does CWE-287 mean for CVE-2026-50751?

CWE-287 refers to Improper Authentication. In the context of this vulnerability, it means the system fails to correctly verify the identity of a user during the connection process. Specifically, the software's logic for checking security certificates is flawed when using the older IKEv1 protocol, which allows attackers to establish a session without providing the correct credentials.

How does an attacker trigger this vulnerability?

An attacker initiates a connection using the deprecated IKEv1 key exchange protocol. The bug is triggered when the system incorrectly validates certificates during this specific handshake. Note that this flaw only exists when the deprecated IKEv1 protocol is enabled; environments that have fully transitioned to newer, more secure protocols for key exchange are not affected by this specific logic error.

Is my network at risk for CVE-2026-50751?

According to Halo Surface Signal, this vulnerability is highly relevant because it targets remote access VPN gateways, which are designed to be internet-facing to support mobile users. If your organization uses these gateways to enable external connectivity, they are likely reachable from the internet, making them a primary point of focus for identifying potential exposure.

What should I do if I manage this technology?

First, audit your infrastructure to identify all active Security Gateways. Determine if the deprecated IKEv1 protocol is currently enabled on any of these devices. If it is, contact your vendor to obtain and apply the specific hotfix or configuration guidance designed to remediate this authentication flaw.

References

Sources and related resources

Primary sources: NVD, CVE.org, CISA KEV.

NVDPublished Modified