SB2026101521 - Multiple vulnerabilities in IBM Fusion and IBM Fusion HCI
Published: October 15, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Insufficient verification of data authenticity (CVE-ID: CVE-2026-56864)
CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity
CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to serve malicious module content to clients.
The vulnerability exists due to improper verification in cmd/go and golang.org/x/mod/sumdb when validating module content from a GOSUMDB and coordinating GOPROXY. A remote attacker can operate a malicious GOSUMDB with a coordinating GOPROXY to serve malicious module content to clients.
Exploitation requires control of both the checksum database and a coordinating module proxy.
2) Insufficient verification of data authenticity (CVE-ID: CVE-2026-56865)
CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity
CVSSv4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass integrity verification and persist attacker-controlled module content in the local Go module cache.
The vulnerability exists due to improper verification of sumdb tiles in cmd/go and golang.org/x/mod/sumdb/tlog when processing responses from a GOPROXY. A remote attacker can serve forged sumdb tiles and malicious module content to bypass integrity verification and persist attacker-controlled module content in the local Go module cache.
This issue requires use of a malicious GOPROXY.
Remediation
Install update from vendor's website.