CVE-2026-43974 Vulnerability Analysis & Exploit Details

CVE-2026-43974
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-43974 Details

Status: Received on 08 Jun 2026, 15:16 UTC

Published on: 08 Jun 2026, 15:16 UTC

CVSS Release:

CVE-2026-43974 Vulnerability Summary

CVE-2026-43974: Unexpected Status Code or Return Value vulnerability in ninenines gun (gun_http module) allows a malicious HTTP server to force the client into raw protocol mode via an unsolicited 101 Switching Protocols response. In gun_http:handle_inform/8, when a 101 Switching Protocols response is received over HTTP/1.1, the function verifies only that the Upgrade header is syntactically valid and that the stream reference is a plain reference(). It does not check whether the client ever sent an Upgrade or Connection: upgrade header on the corresponding request. Because this check is absent, any 101 response (solicited or not) causes gun to dispatch a gun_upgrade message to the caller and transition the entire connection to raw protocol mode. A malicious or compromised HTTP server can send an unsolicited 101 response to any HTTP/1.1 request, causing the gun client to abandon HTTP framing for that connection. Once in raw mode, gun_raw applies no flow control (flow=infinity) and re-arms socket active mode after every received packet, so the server can flood the client with arbitrary bytes. These are forwarded as unbounded gun_data messages to the owner process, exhausting its mailbox and BEAM memory, ultimately crashing the VM. This issue affects gun: from 2.0.0 before 2.4.0.

Assessing the Risk of CVE-2026-43974

Access Complexity Graph

The exploitability of CVE-2026-43974 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-43974

No exploitability data is available for CVE-2026-43974.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-43974, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-43974, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-43974 does not compromise confidentiality.
  • Integrity: None
    CVE-2026-43974 does not impact data integrity.
  • Availability: None
    CVE-2026-43974 does not affect system availability.

CVE-2026-43974 References

External References

CWE Common Weakness Enumeration

CWE-841

Protect Your Infrastructure against CVE-2026-43974: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2026-49975 – Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests. ...
  • CVE-2026-49756 – Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in wojtekmach Req allows multipart parameter smuggling via attacker-infl...
  • CVE-2026-49755 – Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in wojtekmach Req allows attacker-controlled HTTP servers to exhaust...
  • CVE-2026-48913 – Use After Free vulnerability in Apache HTTP Server module mod_http2 when file handles are already exhausted. This issue affects Apache HTTP Server...
  • CVE-2026-48488 – phpMyFAQ is an open source FAQ web application. Prior to version 4.1.4, attachment passwords are hashed using SHA-1, a cryptographically broken alg...