CVE-2026-21850

HCL AION allows untrusted input in response headers

HCL Software · HCL AION

First documented disclosure · Review checkpoint

Summary

Response header injection. Response headers or the structure of a response may be altered.

Severity and exploitation evidence

Medium · 6.5/10 · CVSS 3.1. Severity source.

Exploitation not established: The reviewed public sources describe the vulnerability and its conditions. Malicious exploitation has not been established in the reviewed sources.

Exploitation evidence source

Technical severity is not a measure of observed attacks or of risk to your deployment. Attempts, demonstrations, and successful compromise retain the qualifications in the source.

How the weakness works

Application responses can include user input without correctly separating header values.

Conditions required

An attacker must influence input that reaches an affected response header.

Potential impact

Response headers or the structure of a response may be altered.

Affected versions and configurations

2.6.0.

Fix and mitigation status

2.8.0.

Practical next steps

Upgrade HCL AION to 2.8.0 and verify the affected control in the deployed interface.

Operating lesson

Keep user input out of header structure and validate allowed header values.

Evidence and limits

HCL bulletin KB0135118 was published 2026-11-04 and identifies 2.8.0 as the fix. HCL’s CVE record gives 2026-11-03 as its public date.

Sources