CVE-2026-94444 Go toolchain CVE debrief

Who should care

Defenders responsible for Go projects and GOMODPROXY configurations should assess exposure and prioritize verification of the integrity of these configurations to prevent exploitation.

Why it matters

A checksum bypass vulnerability in the golang.org/fips140 module in cmd/go allows a malicious Go project to serve an arbitrary module in place of the legitimate one when a user operates a malicious GOMODPROXY. Defenders should prioritize verifying the integrity of Go projects and GOMODPROXY configurations to prevent exploitation.

• Verification of Go project and GOMODPROXY configuration integrity is required to prevent exploitation
• Update to versions 1.26.9 or 1.27.2, or later to address the vulnerability
• Monitoring for suspicious activity in Go projects and GOMODPROXY configurations is necessary

Technical summary

The vulnerability allows a malicious Go project to serve an arbitrary module in place of the legitimate golang.org/fips140 module when a user operates a malicious GOMODPROXY. The issue is addressed by unpacking the trusted ziphash for the bundled golang.org/fips140 module and constructing its entry in the GOMODCACHE for verification by the toolchain. Affected product deployments should be verified for exposure, and defenders should prioritize verifying the integrity of Go projects and GOMODPROXY configurations to prevent exploitation.

Defensive priority

Defenders should prioritize verifying the integrity of Go projects and GOMODPROXY configurations to prevent exploitation.

Recommended defensive actions

• Verify the integrity of Go projects and GOMODPROXY configurations
• Update to versions 1.26.9 or 1.27.2, or later
• Monitor for suspicious activity in Go projects and GOMODPROXY configurations
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability is confirmed in the Go toolchain, specifically in the cmd/go module. The issue is addressed in versions 1.26.9 and 1.27.2. However, the exact scope of affected versions requires verification from official sources.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.