CVE-2026-56864

Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb

Published Aug 13, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the transparency log. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Weaknesses CWE-347
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Golang
Golang mod
Gotoolchain
Gotoolchain cmd/go
Vendors & Products Golang
Golang mod
Gotoolchain
Gotoolchain cmd/go
Type Values Removed Values Added
Weaknesses CWE-200
Type Values Removed Values Added
Description A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the transparency log. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy
Title Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Go
Published
Updated
Aug 14, 2026, 4:16 PM
Reserved
Jun 23, 2026, 3:10 PM
Status
Awaiting Analysis
Published
Aug 13, 2026, 10:17 PM
Modified
Sep 3, 2026, 4:37 PM