CVE-2026-79644: Dell SCG 5.0 Auth Bypass Vulnerability

CVE-2026-79644 Overview

CVE-2026-79644 is an Improper Certificate Validation vulnerability [CWE-295] affecting Dell Secure Connect Gateway (SCG) 5.0. The flaw exists in Dell SCG 5.0 Appliance versions prior to 5.36.00.16 and Dell SCG 5.0 Application versions prior to 5.36.00.00. An unauthenticated remote attacker can exploit the weakness to gain unauthorized access to the affected system by presenting a crafted or untrusted certificate that the gateway fails to validate correctly.

Critical Impact
Unauthenticated network attackers can bypass certificate trust checks in Dell SCG 5.0, enabling machine-in-the-middle interception and unauthorized access to protected communications.

Affected Products

Dell Secure Connect Gateway (SCG) 5.0 Appliance versions prior to 5.36.00.16
Dell Secure Connect Gateway (SCG) 5.0 Application versions prior to 5.36.00.00
Dell Secure Connect Gateway Virtual Edition (per DSA-2026-382 advisory)

Discovery Timeline

2026-09-07 - CVE-2026-79644 published to the National Vulnerability Database (NVD)
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-79644

Vulnerability Analysis

CVE-2026-79644 originates from improper certificate validation logic in Dell Secure Connect Gateway. The gateway does not correctly verify the authenticity, chain of trust, or attributes of X.509 certificates presented during TLS negotiation. An attacker positioned to interact with the gateway over the network can supply a certificate that the appliance accepts despite it being invalid, expired, self-signed, or issued by an untrusted authority.

The consequence is a breakdown of the trust boundary that TLS is designed to enforce. Confidentiality and integrity of communications between SCG and connected Dell services or clients can be undermined, allowing an attacker to intercept, read, or manipulate data in transit. Availability is not directly affected.

Root Cause

The root cause is a failure to enforce complete certificate validation in accordance with RFC 5280 requirements. Common patterns behind [CWE-295] include skipping hostname verification, ignoring certificate chain errors, accepting self-signed certificates in production paths, or failing to check revocation status. Dell has not published the specific validation gap, but the DSA-2026-382 advisory confirms the class of defect.

Attack Vector

Exploitation requires network access to the SCG appliance or application. The attacker must occupy a network position that allows presenting a certificate during a TLS handshake initiated by or with the gateway. This typically means a machine-in-the-middle stance on the routing path between SCG and its remote endpoints. No authentication or user interaction is required. Attack complexity is elevated because the adversary must establish the intercept position and time the exchange with a valid TLS session.

No verified public exploit code or proof-of-concept has been observed. See the Dell Security Update DSA-2026-382 for vendor technical details.

Detection Methods for CVE-2026-79644

Indicators of Compromise

Unexpected TLS sessions from SCG to hosts outside the documented Dell backend infrastructure ranges.
Presentation of self-signed or untrusted certificates in packet captures of SCG-initiated TLS handshakes.
Repeated TLS renegotiations or session resets on the network path between SCG and Dell endpoints.

Detection Strategies

Inspect TLS traffic to and from the SCG appliance and log the certificate issuer, subject, and fingerprint for each session.
Compare observed certificate fingerprints against a known-good baseline of Dell service certificates.
Alert on any TLS session from SCG that terminates on a non-Dell IP address or presents a certificate outside the expected trust chain.

Monitoring Recommendations

Forward SCG system logs and network flow data to a centralized analytics platform for continuous review.
Enable network detection and response coverage on the segment hosting SCG to identify machine-in-the-middle patterns such as ARP spoofing or rogue gateway advertisements.
Correlate SCG connection events with authentication anomalies on connected Dell management systems.

How to Mitigate CVE-2026-79644

Immediate Actions Required

Upgrade Dell SCG 5.0 Appliance to version 5.36.00.16 or later immediately.
Upgrade Dell SCG 5.0 Application to version 5.36.00.00 or later immediately.
Restrict network access to the SCG management and data interfaces to trusted segments only.
Review recent SCG connection logs for unexpected remote endpoints or certificate anomalies.

Patch Information

Dell has released fixed versions in DSA-2026-382. Administrators should apply Dell SCG 5.0 Appliance 5.36.00.16 and Dell SCG 5.0 Application 5.36.00.00, or later. Detailed upgrade guidance is provided in the Dell Security Update DSA-2026-382.

Workarounds

Place SCG behind a network segment where TLS interception by unauthorized parties is not feasible.
Enforce strict egress filtering so SCG can only reach documented Dell backend hostnames and IP ranges.
Deploy network monitoring to detect and alert on machine-in-the-middle indicators until the patch is applied.

bash

# Example egress restriction using iptables to limit SCG outbound traffic
# Replace <SCG_IP> and <DELL_ENDPOINT> with values from Dell documentation
iptables -A OUTPUT -s <SCG_IP> -d <DELL_ENDPOINT> -p tcp --dport 443 -j ACCEPT
iptables -A OUTPUT -s <SCG_IP> -p tcp --dport 443 -j DROP