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
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Go toolchain | cmd/go | unaffected |
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| golang.org/x/mod | golang.org/x/mod/sumdb/tlog | unaffected |
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Project Subscriptions
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Advisories
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Fixes
Solution
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Workaround
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References
History
Thu, 13 Aug 2026 22:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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 | |
| Title | Fix transparency log tile verification bypass in golang.org/x/mod/sumdb/tlog | |
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Go
Published:
Updated: 2026-08-13T21:58:53.475Z
Reserved: 2026-06-23T15:10:49.354Z
Link: CVE-2026-56865
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-13T22:17:22.797
Modified: 2026-08-13T22:17:22.797
Link: CVE-2026-56865
Redhat
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OpenCVE Enrichment
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Weaknesses
No weakness.