{"id":"CVE-2026-56864","state":"PUBLISHED","title":"Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb","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","publishedAt":"2026-08-13T21:58:53.605Z","updatedAt":"2026-08-14T16:16:42.248Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"CISA-ADP"},"assigner":"Go","products":["Go toolchain cmd/go","golang.org/x/mod golang.org/x/mod/sumdb"],"affected":[{"vendor":"Go toolchain","product":"cmd/go","packageName":"cmd/go","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.25.13","versionType":"semver"},{"version":"1.26.0-0","status":"affected","lessThan":"1.26.6","versionType":"semver"},{"version":"1.27.0-0","status":"affected","lessThan":"1.27.0-rc.3","versionType":"semver"}],"collectionURL":"https://pkg.go.dev"},{"vendor":"golang.org/x/mod","product":"golang.org/x/mod/sumdb","packageName":"golang.org/x/mod/sumdb","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"0.40.0","versionType":"semver"}],"collectionURL":"https://pkg.go.dev","programRoutines":[{"name":"Client.Lookup"}]}],"references":["https://go.dev/issue/80745","https://groups.google.com/g/golang-announce/c/94pEornpRlI","https://go.dev/cl/815000","https://go.dev/cl/815020","https://pkg.go.dev/vuln/GO-2026-6180"],"weaknesses":["CWE-347"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56864.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56864","state":"PUBLISHED","datePublished":"2026-08-13T21:58:53.605Z","dateUpdated":"2026-08-14T16:16:42.248Z","assignerShortName":"Go","assignerOrgId":"1bb62c36-49e3-4200-9d77-64a1400537cc","dateReserved":"2026-06-23T15:10:49.354Z"},"containers":{"cna":{"title":"Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb","descriptions":[{"lang":"en","value":"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"}],"affected":[{"vendor":"Go toolchain","product":"cmd/go","packageName":"cmd/go","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.25.13","versionType":"semver"},{"version":"1.26.0-0","status":"affected","lessThan":"1.26.6","versionType":"semver"},{"version":"1.27.0-0","status":"affected","lessThan":"1.27.0-rc.3","versionType":"semver"}],"collectionURL":"https://pkg.go.dev"},{"vendor":"golang.org/x/mod","product":"golang.org/x/mod/sumdb","packageName":"golang.org/x/mod/sumdb","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"0.40.0","versionType":"semver"}],"collectionURL":"https://pkg.go.dev","programRoutines":[{"name":"Client.Lookup"}]}],"references":[{"url":"https://go.dev/issue/80745"},{"url":"https://groups.google.com/g/golang-announce/c/94pEornpRlI"},{"url":"https://go.dev/cl/815000"},{"url":"https://go.dev/cl/815020"},{"url":"https://pkg.go.dev/vuln/GO-2026-6180"}],"problemTypes":[{"descriptions":[{"lang":"en","description":"CWE-347: Improper Verification of Cryptographic Signature"}]}],"providerMetadata":{"shortName":"Go","orgId":"1bb62c36-49e3-4200-9d77-64a1400537cc","dateUpdated":"2026-08-13T21:58:53.605Z"},"credits":[{"lang":"en","value":"mundur"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-08-14T16:16:37.911009Z","id":"CVE-2026-56864","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","type":"CWE","lang":"en","description":"CWE-347 Improper Verification of Cryptographic Signature"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-14T16:16:42.248Z"}}]}}}