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 |
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}
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"microsoft_vex": {
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"product_status:known_affected": "5",
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"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": "6"
},
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"versionType": "semver"
},
{
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"version": "1.26.0-0",
"versionType": "semver"
},
{
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{
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}
],
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"version": "0",
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}
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}
],
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"lastModified": "2026-09-03T16:37:52.170",
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}
},
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| Author | Source | Type | Date | Other |
|---|
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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