CVE-2026-55398 in Secure Access
Summary
by MITRE • 07/15/2026
CVE-2026-55398 is a memory management vulnerability in Secure Access clients and servers prior to 14.55. Attackers with intimate knowledge of and total control over the tunnel protocol can create a non-persistent DoS against the server.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a critical memory management flaw affecting Secure Access clients and servers operating on versions prior to 14.55. The issue stems from improper handling of memory allocation and deallocation processes within the tunnel protocol implementation, creating a potential denial of service condition that can be exploited by adversaries with intimate knowledge of the system's internal workings. The vulnerability specifically manifests when attackers manipulate the tunnel protocol to trigger memory corruption conditions that lead to server instability and eventual service disruption.
The technical nature of this flaw lies in how the Secure Access system manages memory resources during tunnel establishment and maintenance phases. When an attacker with complete control over the tunnel protocol communications crafts specific malformed packets or sequences, the system's memory management routines fail to properly handle the resulting edge cases, leading to memory exhaustion or corruption states that ultimately cause the server to become unresponsive. This vulnerability operates at a low-level system interface where network protocol handling intersects with memory allocation mechanisms, making it particularly dangerous as it can be exploited without requiring elevated privileges or complex attack vectors.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire secure access infrastructure. Servers running affected versions become vulnerable to sustained denial of service attacks that can render them unavailable to legitimate users while maintaining the attacker's ability to control the tunnel protocol communications. The non-persistent nature of the attack means that even after the initial exploitation attempt, the server may remain in a compromised state where subsequent connections could be rejected or fail, creating cascading effects across connected systems and networks that depend on secure access services.
Organizations should immediately implement mitigations including patching to version 14.55 or later, which contains corrected memory management routines and enhanced protocol validation mechanisms. Network segmentation and monitoring solutions should be deployed to detect anomalous tunnel protocol behavior that might indicate exploitation attempts. Security teams must also review their incident response procedures to ensure rapid detection and remediation capabilities for this specific vulnerability class. The flaw aligns with CWE-129 and CWE-787 categories related to improper input validation and out-of-bounds writes, while the attack vector maps to ATT&CK techniques involving service stoppage and network disruption. Additional protective measures include implementing rate limiting on tunnel protocol communications, deploying intrusion detection systems specifically configured to identify malicious tunnel protocol sequences, and establishing redundant secure access infrastructure to minimize impact from successful exploitation attempts.