SB2026052653 - Use of hard-coded credentials in KnowledgeDeliver

Description

This security bulletin contains information about 1 vulnerability.

1) Use of hard-coded credentials (CVE-ID: CVE-2026-5426)

CWE-ID: CWE-798 - Use of Hard-coded Credentials

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Red

The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to insecure use of hardcoded cryptographic keys in ASP.NET ViewState handling in the KnowledgeDeliver ASP.NET application configuration when processing a crafted __VIEWSTATE parameter in an HTTP request. A remote attacker can send a specially crafted ViewState payload to execute arbitrary code.

The issue arises because identical pre-shared ASP.NET machine keys were used across multiple customer deployments, allowing compromise of other internet-facing instances if the keys were obtained from one deployment.

Note, the vulnerability is being actively exploited in the wild. 

Remediation

Install update from vendor's website.

References

• https://cloud.google.com/blog/topics/threat-intelligence/knowledgedeliver-viewstate-deserialization-vulnerability
• https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0009.md