CVE-2026-64651

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% 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: epss, secondary
6.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.3Exploit: None knownExposed: 0

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

The @ai-sdk/harness-opencode tool connects HarnessAgent to OpenCode through a sandboxed bridge. Prior to version 1.0.28, the tool relay authorizes requests from any process whose command line contains an allowed helper script path (host-tool-mcp.mjs). This allows untrusted code executing in the sandbox to invoke arbitrary host-exposed tools including secret lookups, deployment operations, and cloud API calls without a corresponding model-authorized tool-call event. Exploitation requires a Linux environment (the vulnerable fallback checks process.platform === 'linux' and reads /proc); an active harness session with one or more host-provided tools; and untrusted code executing in the sandbox (e.g. a malicious dependency, build script, or lifecycle hook) The fix in version 1.0.28 removes the process-path authorization fallback entirely. Relay requests are now only accepted after exact, short-lived, one-time authorization matching the tool name and input from a bridge-observed model event. Some workarounds are available. Do not run the OpenCode harness on untrusted repositories or with untrusted dependencies, and/or limit host-exposed tools to non-sensitive operations when working with untrusted code.

CVSS v3
6.3
EG Score
6.3(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity63% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

July 20, 2026

Last Modified

July 23, 2026

Advisory Details (2)

Auto-updated Jul 20, 2026
Patch available. Sources: github, github_pr.
github_pr Patch Available

fix(harness): improve CLI relay tool invocation logic

Patch available: vercel/ai [email protected] (PR #17105 merged 2026-07-10)

https://github.com/vercel/ai/pull/17105
github Patch Available

AI SDK OpenCode Harness Tool Relay Authorization Bypass · Advisory · vercel/ai · GitHub

https://github.com/vercel/ai/security/advisories/GHSA-g48p-5rr5-8rgq

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 21× 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. 2026-07-30 17:07 UTCEG score recompute
  2. 2026-07-30 16:28 UTCEPSS rescore
  3. 2026-07-30 01:30 UTCEPSS rescore
  4. 2026-07-30 01:30 UTCEPSS rescore
  5. 2026-07-28 21:24 UTCEG score recompute
  6. 2026-07-28 15:37 UTCEPSS rescore
  7. 2026-07-27 02:06 UTCEG score recompute
  8. 2026-07-26 04:26 UTCEG score recompute
  9. 2026-07-25 14:18 UTCEPSS rescore
  10. 2026-07-25 14:18 UTCEPSS rescore
  11. 2026-07-24 14:18 UTCEPSS rescore
  12. 2026-07-24 14:18 UTCEPSS rescore
  13. 2026-07-23 03:22 UTCEG score recompute
  14. 2026-07-22 14:08 UTCEPSS rescore
  15. 2026-07-22 14:08 UTCEPSS rescore
  16. 2026-07-21 15:25 UTCEPSS rescore
  17. 2026-07-21 15:25 UTCEPSS rescore
  18. 2026-07-21 14:31 UTCEG score recompute
  19. 2026-07-20 22:42 UTCEG score recompute
  20. 2026-07-20 20:53 UTCEG score recompute
  21. 2026-07-20 20:52 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-64651?
CVE-2026-64651 is a medium vulnerability published on July 20, 2026. The @ai-sdk/harness-opencode tool connects HarnessAgent to OpenCode through a sandboxed bridge. Prior to version 1.0.28, the tool relay authorizes requests from any process whose command line contains an allowed helper script path (host-tool-mcp.mjs). This allows untrusted code executing in the…
When was CVE-2026-64651 disclosed?
CVE-2026-64651 was first published in the National Vulnerability Database on July 20, 2026, with the most recent update on July 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64651 actively exploited?
CVE-2026-64651 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 98.4% of all scored CVEs.
What is the CVSS score of CVE-2026-64651?
CVE-2026-64651 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-64651?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64651, 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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