CVE-2026-56864 (GCVE-0-2026-56864)
Vulnerability from cvelistv5 – Published: 2026-08-13 21:58 – Updated: 2026-08-14 16:16
VLAI
EPSS
VEX
Title
Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb
Summary
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
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-14 16:16 UTC
CWE
- CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Go toolchain | cmd/go |
Affected:
0 , < 1.25.13
(semver)
Affected: 1.26.0-0 , < 1.26.6 (semver) Affected: 1.27.0-0 , < 1.27.0-rc.3 (semver) |
guessed | |
| golang.org/x/mod | golang.org/x/mod/sumdb |
Affected:
0 , < 0.40.0
(semver)
|
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-56864",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-14T16:16:37.911009Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-347",
"description": "CWE-347 Improper Verification of Cryptographic Signature",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-14T16:16:42.248Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "cmd/go",
"product": "cmd/go",
"vendor": "Go toolchain",
"versions": [
{
"lessThan": "1.25.13",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"lessThan": "1.26.6",
"status": "affected",
"version": "1.26.0-0",
"versionType": "semver"
},
{
"lessThan": "1.27.0-rc.3",
"status": "affected",
"version": "1.27.0-0",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "golang.org/x/mod/sumdb",
"product": "golang.org/x/mod/sumdb",
"programRoutines": [
{
"name": "Client.Lookup"
}
],
"vendor": "golang.org/x/mod",
"versions": [
{
"lessThan": "0.40.0",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"value": "mundur"
}
],
"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/ \u0026\u0026 go mod tidy"
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-347: Improper Verification of Cryptographic Signature",
"lang": "en"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-13T21:58:53.605Z",
"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"shortName": "Go"
},
"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"
}
],
"title": "Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb"
}
},
"cveMetadata": {
"assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"assignerShortName": "Go",
"cveId": "CVE-2026-56864",
"datePublished": "2026-08-13T21:58:53.605Z",
"dateReserved": "2026-06-23T15:10:49.354Z",
"dateUpdated": "2026-08-14T16:16:42.248Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-56864",
"date": "2026-09-20",
"epss": "0.00298",
"percentile": "0.22683"
},
"microsoft_vex": {
"current_release_date": "2026-09-17T01:52:14.000Z",
"cve": "CVE-2026-56864",
"id": "msrc_CVE-2026-56864",
"initial_release_date": "2026-08-20T22:00:59.000Z",
"product_status:known_affected": "5",
"product_status:known_not_affected": "3",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-56864.json",
"version": "5"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "cmd/go",
"product": "cmd/go",
"vendor": "Go toolchain",
"versions": [
{
"lessThan": "1.25.13",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"lessThan": "1.26.6",
"status": "affected",
"version": "1.26.0-0",
"versionType": "semver"
},
{
"lessThan": "1.27.0-rc.3",
"status": "affected",
"version": "1.27.0-0",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "golang.org/x/mod/sumdb",
"product": "golang.org/x/mod/sumdb",
"programRoutines": [
{
"name": "Client.Lookup"
}
],
"vendor": "golang.org/x/mod",
"versions": [
{
"lessThan": "0.40.0",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"source": "security@golang.org"
}
],
"cveTags": [],
"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/ \u0026\u0026 go mod tidy"
}
],
"id": "CVE-2026-56864",
"lastModified": "2026-09-03T16:37:52.170",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-56864",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-14T16:16:37.911009Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-08-13T22:17:22.677",
"references": [
{
"source": "security@golang.org",
"url": "https://go.dev/cl/815000"
},
{
"source": "security@golang.org",
"url": "https://go.dev/cl/815020"
},
{
"source": "security@golang.org",
"url": "https://go.dev/issue/80745"
},
{
"source": "security@golang.org",
"url": "https://groups.google.com/g/golang-announce/c/94pEornpRlI"
},
{
"source": "security@golang.org",
"url": "https://pkg.go.dev/vuln/GO-2026-6180"
}
],
"sourceIdentifier": "security@golang.org",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-347"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-09-10T16:19:05+00:00",
"cve": "CVE-2026-56864",
"id": "CVE-2026-56864",
"initial_release_date": "2026-08-13T21:58:53.605000+00:00",
"product_status:known_affected": "9",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "golang.org/x/mod/sumdb: golang.org/x/mod/sumdb: Integrity bypass via malicious GOSUMDB",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56864.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "moderate",
"current_release_date": "2026-08-31T16:37:01Z",
"cve": "CVE-2026-56864",
"id": "CVE-2026-56864",
"initial_release_date": "2026-08-14T23:48:51Z",
"product_status:first_fixed": "12",
"product_status:known_affected": "12",
"product_status:known_not_affected": "143",
"product_status:recommended": "262",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-56864",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-56864.json",
"version": "6"
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-56864",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-14T16:16:37.911009Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-347",
"description": "CWE-347 Improper Verification of Cryptographic Signature",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-14T16:16:22.544Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "cmd/go",
"product": "cmd/go",
"vendor": "Go toolchain",
"versions": [
{
"lessThan": "1.25.13",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"lessThan": "1.26.6",
"status": "affected",
"version": "1.26.0-0",
"versionType": "semver"
},
{
"lessThan": "1.27.0-rc.3",
"status": "affected",
"version": "1.27.0-0",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "golang.org/x/mod/sumdb",
"product": "golang.org/x/mod/sumdb",
"programRoutines": [
{
"name": "Client.Lookup"
}
],
"vendor": "golang.org/x/mod",
"versions": [
{
"lessThan": "0.40.0",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"value": "mundur"
}
],
"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/ \u0026\u0026 go mod tidy"
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-347: Improper Verification of Cryptographic Signature",
"lang": "en"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-13T21:58:53.605Z",
"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"shortName": "Go"
},
"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"
}
],
"title": "Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb"
}
},
"cveMetadata": {
"assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"assignerShortName": "Go",
"cveId": "CVE-2026-56864",
"datePublished": "2026-08-13T21:58:53.605Z",
"dateReserved": "2026-06-23T15:10:49.354Z",
"dateUpdated": "2026-08-13T21:58:53.605Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…