CVE-2026-21826 Vulnerability Analysis & Exploit Details

CVE-2026-21826
Vulnerability Scoring

6.1
/10
High Risk

If left unpatched, CVE-2026-21826 could lead to major system disruptions or data loss.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: Required
    User interaction is necessary for successful exploitation.

CVE-2026-21826 Details

Status: Received on 05 Jun 2026, 07:16 UTC

Published on: 05 Jun 2026, 07:16 UTC

CVSS Release: version 3

CVSS3 Source

psirt@hcl.com

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2026-21826 Vulnerability Summary

CVE-2026-21826: HCL Digital Experience and HCL Digital Experience Compose could be susceptible to Host header injection.  An attacker can manipulate the Host header and cause the application to behave in unexpected ways.

Assessing the Risk of CVE-2026-21826

Access Complexity Graph

The exploitability of CVE-2026-21826 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-2026-21826

With low attack complexity and no required privileges, CVE-2026-21826 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

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-2026-21826, 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-2026-21826, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: Low
    CVE-2026-21826 could lead to minor leaks of non-critical information without major privacy breaches.
  • Integrity: Low
    Exploiting CVE-2026-21826 may cause minor changes to data without severely impacting its accuracy.
  • Availability: None
    CVE-2026-21826 does not impact system availability.

CVE-2026-21826 References

External References

CWE Common Weakness Enumeration

CWE-601

CAPEC Common Attack Pattern Enumeration and Classification

  • Cross-Site Flashing CAPEC-178 An attacker is able to trick the victim into executing a Flash document that passes commands or calls to a Flash player browser plugin, allowing the attacker to exploit native Flash functionality in the client browser. This attack pattern occurs where an attacker can provide a crafted link to a Flash document (SWF file) which, when followed, will cause additional malicious instructions to be executed. The attacker does not need to serve or control the Flash document. The attack takes advantage of the fact that Flash files can reference external URLs. If variables that serve as URLs that the Flash application references can be controlled through parameters, then by creating a link that includes values for those parameters, an attacker can cause arbitrary content to be referenced and possibly executed by the targeted Flash application.

Protect Your Infrastructure against CVE-2026-21826: Combat Critical CVE Threats

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