CVE-2026-78130 in strongSwan
Summary
by MITRE • 09/11/2026
strongSwan 4.2.0 through 6.0.7 has a NULL pointer dereference in the x509 plugin's attribute certificate parser.
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Analysis
by VulDB Data Team • 09/11/2026
The vulnerability identified in strongSwan versions ranging from 4.2.0 to 6.0.7 represents a critical memory safety flaw located within the X.509 extension module, specifically affecting the parsing logic for Attribute Certificates. This component is responsible for processing certificate attributes that define user roles or permissions rather than identity, which are essential in complex Public Key Infrastructure environments where fine-grained access control is required. The core technical defect involves a NULL pointer dereference triggered during the validation and extraction of specific attribute fields within an incoming Certificate Revocation List (CRL) extension or Attribute Certificate structure. When the parser encounters malformed input data that fails to meet expected structural constraints, it proceeds to reference memory locations without verifying if the underlying pointers have been properly initialized or allocated by preceding parsing steps. This lack of defensive programming allows a crafted packet containing specially constructed ASN.1 encoded data to cause the application to attempt accessing invalid memory addresses, resulting in an immediate segmentation fault and process termination.
From a security operations perspective, this vulnerability poses a significant risk regarding service availability within IPsec deployments that rely on strongSwan for certificate-based authentication. Since the flaw is triggered during the parsing of incoming network traffic related to certificate validation, it can be exploited remotely by an attacker positioned in the path of communication or capable of injecting packets into the control plane. An adversary could send a maliciously crafted Attribute Certificate request designed to trigger this NULL pointer dereference, causing the strongSwan daemon to crash repeatedly. This constitutes a classic Denial of Service scenario where the integrity and availability of the VPN gateway are compromised without requiring any authentication credentials. In high-availability clusters or critical infrastructure networks relying on continuous IPsec tunnel maintenance, such instability can lead to widespread connectivity loss and operational disruption for all connected clients.
The technical classification of this flaw aligns with CWE-476, which denotes a NULL Pointer Dereference vulnerability. This category encompasses errors where software dereferences a pointer that it expects to be valid but is actually null, leading to crashes or unintended control flow transfers. In the context of network daemons like strongSwan, such memory corruption issues are particularly dangerous because they often occur in privileged processes handling sensitive cryptographic material and connection states. Furthermore, this vulnerability can be contextualized within MITRE ATT&CK framework techniques related to Resource Hijacking or Denial of Service via application layer attacks, specifically under the tactic of Impact where an attacker aims to disrupt service availability rather than exfiltrate data or gain persistent access. The exploitation vector is typically classified as Network-based with Low Complexity, allowing for automated remote exploitation by any actor who can reach the vulnerable port and protocol implementation.
Mitigation strategies must prioritize immediate patching to a version of strongSwan that includes fixes for this parsing logic error, ensuring that all pointer validations are robust against malformed ASN.1 structures. Administrators should verify their current deployment versions and apply updates provided by distribution maintainers or upstream sources as soon as they become available. In environments where upgrading is not immediately feasible, network-level mitigations such as strict ingress filtering on ports used for IKEv2 negotiations can help reduce the attack surface. Additionally, implementing deep packet inspection solutions capable of detecting anomalous ASN.1 structures before they reach the application layer may provide a temporary buffer against exploitation attempts until the software patch is deployed. Regular auditing of certificate validation logs and monitoring for unexpected daemon restarts or core dumps are also recommended to detect potential probing activities targeting this specific weakness in real-time.