CVE-2026-55655 Vulnerability Analysis & Exploit Details

CVE-2026-55655
Vulnerability Scoring

5.0
/10
Medium Risk

The vulnerability CVE-2026-55655 could compromise system integrity but typically requires user interaction to be exploited.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Local
    Vulnerability requires local system access.
  • Privileges Required: Low
    Some privileges are necessary to exploit the vulnerability.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: Required
    User interaction is necessary for successful exploitation.

CVE-2026-55655 Details

Status: Received on 23 Jun 2026, 04:17 UTC

Published on: 23 Jun 2026, 04:17 UTC

CVSS Release: version 3

CVSS3 Source

secalert@redhat.com

CVSS3 Type

Primary

CVSS3 Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N

CVE-2026-55655 Vulnerability Summary

CVE-2026-55655: A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

Assessing the Risk of CVE-2026-55655

Access Complexity Graph

The exploitability of CVE-2026-55655 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-2026-55655

This vulnerability, CVE-2026-55655, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.

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-2026-55655, 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-2026-55655, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-55655 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: Low
    Exploiting CVE-2026-55655 may cause minor changes to data without severely impacting its accuracy.
  • Availability: None
    CVE-2026-55655 does not impact system availability.

CVE-2026-55655 References

External References

CWE Common Weakness Enumeration

CWE-923

CAPEC Common Attack Pattern Enumeration and Classification

  • Infrastructure Manipulation CAPEC-161 An attacker exploits characteristics of the infrastructure of a network entity in order to perpetrate attacks or information gathering on network objects or effect a change in the ordinary information flow between network objects. Most often, this involves manipulation of the routing of network messages so, instead of arriving at their proper destination, they are directed towards an entity of the attackers' choosing, usually a server controlled by the attacker. The victim is often unaware that their messages are not being processed correctly. For example, a targeted client may believe they are connecting to their own bank but, in fact, be connecting to a Pharming site controlled by the attacker which then collects the user's login information in order to hijack the actual bank account.
  • Contradictory Destinations in Traffic Routing Schemes CAPEC-481 Adversaries can provide contradictory destinations when sending messages. Traffic is routed in networks using the domain names in various headers available at different levels of the OSI model. In a Content Delivery Network (CDN) multiple domains might be available, and if there are contradictory domain names provided it is possible to route traffic to an inappropriate destination. The technique, called Domain Fronting, involves using different domain names in the SNI field of the TLS header and the Host field of the HTTP header. An alternative technique, called Domainless Fronting, is similar, but the SNI field is left blank.
  • Android Activity Hijack CAPEC-501 An adversary intercepts an implicit intent sent to launch a Android-based trusted activity and instead launches a counterfeit activity in its place. The malicious activity is then used to mimic the trusted activity's user interface and prompt the target to enter sensitive data as if they were interacting with the trusted activity.
  • DHCP Spoofing CAPEC-697 An adversary masquerades as a legitimate Dynamic Host Configuration Protocol (DHCP) server by spoofing DHCP traffic, with the goal of redirecting network traffic or denying service to DHCP.

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