CVE-2026-59900 Vulnerability Analysis & Exploit Details

CVE-2026-59900
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-2026-59900 Details

Status: Received on 29 Jul 2026, 18:16 UTC

Published on: 29 Jul 2026, 18:16 UTC

CVSS Release:

CVE-2026-59900 Vulnerability Summary

CVE-2026-59900: Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, Netty's HTTP/2-to-HTTP/1.x translation layer (`Http2StreamFrameToHttpObjectCodec` and `InboundHttp2ToHttpAdapter`) fails to deduplicate or validate `Host` headers when an HTTP/2 client supplies both the `:authority` pseudo-header and a literal `host` header in a single HEADERS frame. The translator maps `:authority` to `Host` and separately copies the literal `host` header, producing an `HttpRequest` object containing two `Host` headers with attacker-controlled differing values. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

Assessing the Risk of CVE-2026-59900

Access Complexity Graph

The exploitability of CVE-2026-59900 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-2026-59900

No exploitability data is available for CVE-2026-59900.

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-2026-59900, 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-2026-59900, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-59900 does not compromise confidentiality.
  • Integrity: None
    CVE-2026-59900 does not impact data integrity.
  • Availability: None
    CVE-2026-59900 does not affect system availability.

CVE-2026-59900 References

External References

CWE Common Weakness Enumeration

CWE-444

CAPEC Common Attack Pattern Enumeration and Classification

  • HTTP Response Smuggling CAPEC-273 An adversary manipulates and injects malicious content in the form of secret unauthorized HTTP responses, into a single HTTP response from a vulnerable or compromised back-end HTTP agent (e.g., server). See CanPrecede relationships for possible consequences. Modification/manipulation of HTTP message headers, request-line and body parameters to disrupt and interfere in the interpretation and parsing of HTTP message lengths/boundaries for consecutive HTTP messages by HTTP agents in a HTTP chain or network path.
  • HTTP Request Smuggling CAPEC-33 An adversary abuses the flexibility and discrepancies in the parsing and interpretation of HTTP Request messages using various HTTP headers, request-line and body parameters as well as message sizes (denoted by the end of message signaled by a given HTTP header) by different intermediary HTTP agents (e.g., load balancer, reverse proxy, web caching proxies, application firewalls, etc.) to secretly send unauthorized and malicious HTTP requests to a back-end HTTP agent (e.g., web server). See CanPrecede relationships for possible consequences. Modification/manipulation of HTTP message headers, request-line and body parameters to disrupt and interfere in the interpretation and parsing of HTTP message lengths/boundaries for consecutive HTTP messages by HTTP agents in a HTTP chain or network path.

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