CVE-2026-95395

Executive Summary

CVE-2026-95395 is a memory leak vulnerability in the IEEE C37.118 Synchrophasor protocol dissector affecting the specified product versions. An attacker can trigger a denial of service (DoS) condition by causing a memory leak during dissection, leading to resource exhaustion. The CVSS score is 5.5, indicating a medium-severity issue, but it can disrupt availability in environments relying on the affected product, such as network monitoring or industrial control systems.

Technical Analysis

The vulnerability resides in the IEEE C37.118 Synchrophasor protocol dissector, which is responsible for parsing network traffic related to synchrophasor data. The flaw is classified as CWE-401: Missing Release of Memory after Effective Lifetime. This means that under certain conditions, the dissector fails to release memory that it has allocated, resulting in a memory leak. Over time, repeated triggering of this leak can exhaust available memory, leading to a denial of service condition where the application becomes unresponsive or crashes. The attack vector is local (AV:L), requiring user interaction (UI:R) and no privileges (PR:N). The impact is solely on availability (A:H), with no effect on confidentiality or integrity. The exact code-level cause is not detailed in the available description, but the vulnerability class suggests improper memory management in the dissector's handling of malformed or unexpected C37.118 packets.

Exploitation Scenarios

The exploitation of CVE-2026-95395 follows a typical pattern for memory leak vulnerabilities:

1. Reconnaissance/Target Identification: An attacker identifies a system running the vulnerable product and processes C37.118 traffic. This could be a network monitoring station, a SCADA system, or any environment where the product dissects synchrophasor protocol data. The attacker needs to be able to deliver crafted packets to the target, either locally or via a network path that the dissector processes.

2. Triggering the Flaw: The attacker crafts or obtains a malformed IEEE C37.118 packet that exploits the dissector's memory management flaw. The exact packet structure is not specified in the available data, but it likely involves unexpected field lengths, missing fields, or specific sequences that cause the dissector to allocate memory without subsequently freeing it. Since the vulnerability is a memory leak, the attacker may need to send multiple packets over time to accumulate the leak and cause resource exhaustion.

3. Payload/Execution Method: No public PoC or exploit code is available. The attack is at the vulnerability-class level: sending crafted C37.118 packets to the target system. The attacker does not execute arbitrary code; instead, they cause the application to consume increasing amounts of memory, eventually leading to a denial of service. The user interaction requirement (UI:R) suggests that a user may need to open a malicious packet capture file or otherwise initiate processing of the crafted data.

4. Post-Exploitation Impact: Successful exploitation results in a denial of service. The affected application may become unresponsive, crash, or be forcibly terminated due to memory exhaustion. This can disrupt network monitoring, industrial control operations, or any process relying on the affected product for C37.118 protocol analysis. The availability impact is high, but confidentiality and integrity are unaffected.

Impact Assessment

The CVSS v3.1 score is 5.5 (Medium), with the vector CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. This indicates:

• Attack Vector (AV:L): The attack requires local access or a local delivery mechanism, such as a malicious file or local network traffic.
• Attack Complexity (AC:L): No special conditions are required beyond crafting the malicious input.
• Privileges Required (PR:N): The attacker does not need any privileges.
• User Interaction (UI:R): A user must perform some action, such as opening a file or initiating a capture.
• Scope (S:U): The impact is confined to the vulnerable component.
• Confidentiality (C:N): No impact on data confidentiality.
• Integrity (I:N): No impact on data integrity.
• Availability (A:H): High impact on availability, leading to a denial of service.

The blast radius is limited to systems that process C37.118 traffic with the vulnerable product. In industrial control systems (ICS) or critical infrastructure monitoring, this could cause loss of visibility into synchrophasor data, potentially affecting situational awareness and grid reliability. The memory leak may require sustained attack to fully exhaust resources, but even partial exhaustion can degrade performance.

Detection Guidance

Sigma Rule

title: Potential IEEE C37.118 Synchrophasor Dissector Memory Leak DoS
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects excessive memory consumption or crashes in the affected product when processing C37.118 traffic.
author: Threat Intelligence
date: 2026-01-01
logsource:
  category: application
  product: windows
  service: application
detection:
  selection:
    EventID: 1000  # Application Error
    Provider_Name: 'wireshark.exe'  # or the specific product executable
    Message|contains: 'memory'
  condition: selection
falsepositives:
  - Legitimate high memory usage
level: medium

YARA Rule

rule CVE_2026_95395_MemoryLeak_C37_118
{
    meta:
        description = "Detects potential exploitation of CVE-2026-95395 via memory leak patterns in C37.118 dissector"
        author = "Threat Intelligence"
        date = "2026-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-95395"
        severity = "medium"
    strings:
        $c37_118 = { 00 01 ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? } // Simplified C37.118 header pattern
    condition:
        $c37_118 and filesize < 10MB
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2026-95395 IEEE C37.118 Synchrophasor Dissector Memory Leak DoS Attempt"; flow:to_server,established; content:"|00 01|"; depth:2; byte_test:1,>,0,2; classtype:attempted-dos; sid:10000001; rev:1;)

Elastic Detection

process where process.name == "wireshark.exe" and event.category == "process" and event.action == "memory_exhaustion"

Splunk SPL Query

index=main source="wireshark" (EventCode=1000 OR "memory leak" OR "out of memory") | stats count by host, process_name, message

Wazuh OSSEC Rule

<group name="wireshark,cve-2026-95395,">
  <rule id="100001" level="10">
    <decoded_as>json</decoded_as>
    <field name="event_type">memory_leak</field>
    <description>CVE-2026-95395: IEEE C37.118 dissector memory leak detected</description>
    <mitre>
      <id>T1499</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence is 0/4 (UNPATCHED — no patch evidence from any tracked source). Immediate mitigations include:

1. Disable C37.118 Dissector: If not required, disable the IEEE C37.118 Synchrophasor protocol dissector in the affected product to prevent processing of malicious packets.
2. Limit Exposure: Restrict access to systems running the vulnerable product, especially from untrusted networks. Avoid opening untrusted packet capture files.
3. Monitor Memory Usage: Implement monitoring for abnormal memory consumption in the affected application and restart it periodically to clear leaks.
4. Network Segmentation: Isolate systems that process C37.118 traffic to reduce the attack surface.
5. Patch/Upgrade Steps: No patch is currently available. Monitor vendor advisories for updates. Once a fixed version is released, upgrade immediately.
6. Long-Term Hardening: Apply the principle of least privilege, regularly update software, and conduct security reviews of protocol dissectors. Consider using memory-safe languages or static analysis tools to detect similar issues.

References

1. NVD – CVE-2026-95395: https://nvd.nist.gov/vuln/detail/CVE-2026-95395
2. CWE-401: Missing Release of Memory after Effective Lifetime: https://cwe.mitre.org/data/definitions/401.html
3. MITRE ATT&CK T1499 – Endpoint Denial of Service: https://attack.mitre.org/techniques/T1499/
4. IEEE C37.118 Standard for Synchrophasor Data Transfer: https://standards.ieee.org/standard/C37_118-2011.html
5. CISA KEV Catalog: Not applicable (CVE not listed as of current data).