CVE-2026-56864

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 78% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cisa-adp, epss
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

August 13, 2026

Last Modified

August 14, 2026

Advisory Details (5)

Auto-updated Aug 14, 2026
No patch confirmed yet.
generic

GO-2026-6180 - Go Packages

https://pkg.go.dev/vuln/GO-2026-6180
generic
https://go.dev/cl/815020
generic
https://go.dev/cl/815000
generic
https://groups.google.com/g/golang-announce/c/94pEornpRlI
generic

x/mod/sumdb: ignore unrelated, unauthenticated hashes in Lookup · Issue #80745 · golang/go · GitHub

https://go.dev/issue/80745

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-26 14:46 UTCEPSS rescore
  2. 2026-08-25 21:57 UTCEG score recompute
  3. 2026-08-25 13:49 UTCEPSS rescore
  4. 2026-08-24 21:36 UTCEG score recompute
  5. 2026-08-23 08:56 UTCEG score recompute
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-22 08:37 UTCEG score recompute
  8. 2026-08-21 23:49 UTCEPSS rescore
  9. 2026-08-21 08:17 UTCEG score recompute
  10. 2026-08-20 22:55 UTCEPSS rescore
  11. 2026-08-19 19:47 UTCEG score recompute
  12. 2026-08-19 17:04 UTCEPSS rescore
  13. 2026-08-18 19:27 UTCEG score recompute
  14. 2026-08-18 13:48 UTCEPSS rescore
  15. 2026-08-17 19:07 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 18:14 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 06:03 UTCEG score recompute
  20. 2026-08-16 02:14 UTCEPSS rescore
  21. 2026-08-15 05:44 UTCEG score recompute
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 16:25 UTCEG score recompute▲ 7.50
  24. 2026-08-14 16:24 UTCMITRE cvelistV5CVSS v3 → 7.5 · severity → HIGH
  25. 2026-08-13 22:25 UTCNVD update
Show 2 more
  1. 2026-08-13 22:09 UTCEG score recompute
  2. 2026-08-13 22:09 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-56864?
CVE-2026-56864 is a high vulnerability published on August 13, 2026. 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…
When was CVE-2026-56864 disclosed?
CVE-2026-56864 was first published in the National Vulnerability Database on August 13, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56864 actively exploited?
CVE-2026-56864 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 78.1% of all scored CVEs.
What is the CVSS score of CVE-2026-56864?
CVE-2026-56864 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-56864?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56864, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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