CVE-2026-56865
HighCVSS 8.4Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy
Risk Assessment
The organization may download and use malicious code from Go modules, potentially leading to application compromise or malware injection.
Recommendation
Update Go tooling to a patched version and run the provided commands to verify module integrity.
Original NVD description (English source)
A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy