FrontMCP is a TypeScript-first framework for the Model Context Protocol (MCP). From mcp-from-openapi 2.3.0 until 2.5.0 and from frontmcp and @frontmcp/adapters 1.2.1 until 1.5.0, libs/adapters/src/openapi/openapi.adapter.ts loadOpenAPISpec() forwards untrusted OpenAPI url and spec inputs and loadOptions.refResolution to OpenAPIToolGenerator.fromURL() and OpenAPIToolGenerator.fromJSON(). The external $ref guard checks parsed hostname strings without resolving addresses, pinning validated addresses, revalidating redirect targets, or normalizing IPv4-mapped IPv6. An authenticated user who can import or configure an OpenAPI specification in a hosted or multi-user deployment can use DNS-to-loopback resolution, redirect-to-loopback behavior, or IPv4-mapped IPv6 loopback forms to cause backend-origin requests to internal services. This can expose internal administrative APIs, metadata-like services, and other private network endpoints. The practical impact is lower when only a trusted local administrator can configure OpenAPI specs, and disabling external reference protocols prevents the external $ref request. This issue is fixed in mcp-from-openapi 2.5.0 and frontmcp and @frontmcp/adapters 1.5.0.
CVE-2026-59973
“—” beside the score: it is equal to the CVSS score beside it.
Score 8.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-11. A secondary CVSS source baseline 8.5; sources differ by 0.0.
Also known asEUVD-2026-78782 (ENISA EUVD) · GHSA-65h7-9wrw-629c (GitHub Security Advisories)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 8.5
- EG Score
- 8.5HIGHmedium confidence
- EG Risk
- 54EG Risk 54/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity85% × 45%Impact severity (EG Severity): CVSS 8.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.4%
- EPSS %ILE
- 33rd
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.5): severity, escalated by confirmed exploitation. This CVE's 8.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
September 11, 2026
Last Modified
September 30, 2026
Advisory Details (7)
Auto-updated Sep 15, 2026v2.5.0
Patch available: agentfront/mcp-from-openapi v2.5.0
https://github.com/agentfront/mcp-from-openapi/releases/tag/v2.5.0v1.5.0
Patch available: agentfront/frontmcp v1.5.0
https://github.com/agentfront/frontmcp/releases/tag/v1.5.0commit be3409cce6e9 (agentfront/mcp-from-openapi)
Patch available: agentfront/mcp-from-openapi v2.5.0 (contains commit be3409cce6e9)
https://github.com/agentfront/mcp-from-openapi/commit/be3409cce6e97642696d4ee5a4e4e2712490b277commit 96a78eaa5c6c (agentfront/frontmcp)
Patch available: agentfront/frontmcp v1.5.0 (contains commit 96a78eaa5c6c)
https://github.com/agentfront/frontmcp/commit/96a78eaa5c6c4bc51cced557d83d1a03344cb03dfeat(ssrf): implement SSRF protection for spec loading and external $ref resolution
Patch available: agentfront/mcp-from-openapi v2.5.0 (PR #7 merged 2026-06-21)
https://github.com/agentfront/mcp-from-openapi/pull/7feat: add validation for package manifests and enhance SSRF protection in OpenAPI adapter
Patch available: agentfront/frontmcp v1.5.0 (PR #496 merged 2026-06-21)
https://github.com/agentfront/frontmcp/pull/496Bypass of OpenAPI external $ref SSRF fix in latest FrontMCP and mcp-from-openapi · Advisory · agentfront/frontmcp · GitHub
https://github.com/agentfront/frontmcp/security/advisories/GHSA-65h7-9wrw-629cVendor Advisories for CVE-2026-59973(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(2)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| npm | frontmcp @ 1.5.0 (fixes >= 1.2.1, < 1.5.0) | — | ghsa |
| npm | mcp-from-openapi @ 2.5.0 (fixes >= 2.3.0, < 2.5.0) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(3 across 1 ecosystem)
npm(3)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| frontmcp | — |
| — |
| @frontmcp/adapters | — |
| — |
| mcp-from-openapi | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 49× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-11-01 07:41 UTCGHSA enrichmentGHSA-65h7-9wrw-629c · GitHub severity HIGH · GitHub CVSS 8.5
- 2026-11-01 07:41 UTCEG score recompute
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-27 18:56 UTCEG score recompute
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
- 2026-10-25 14:16 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
- 2026-10-20 09:37 UTCEG score recompute
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-18 03:26 UTCEG score recompute
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
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- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-13 15:42 UTCEG score recompute
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-12 15:52 UTCEG score recompute
- 2026-10-11 19:36 UTCEG score recompute
- 2026-10-11 16:51 UTCEG score recompute
- 2026-10-11 14:13 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-11 06:45 UTCEG score recompute
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-10 04:18 UTCEG score recompute
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-08 23:10 UTCEG score recompute
- 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-08 07:12 UTCEG score recompute
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-06 19:05 UTCEG score recompute
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-05 19:06 UTCEG score recompute
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-05 07:12 UTCEG score recompute
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-03 18:53 UTCEG score recompute
- 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-02 18:50 UTCEG score recompute
- 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-02 06:57 UTCEG score recompute
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-09-30 18:09 UTCEG score recompute
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-30 01:38 UTCEG score recompute
- 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-29 08:17 UTCEG score recompute
- 2026-09-28 20:24 UTCEG score recompute
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-27 20:38 UTCEG score recompute
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-26 20:51 UTCEG score recompute
- 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-26 08:58 UTCEG score recompute
- 2026-09-24 19:10 UTCEG score recompute
- 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 30th percentile
- 2026-09-23 19:25 UTCEG score recompute
- 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-09-22 18:38 UTCEG score recompute
- 2026-09-22 06:45 UTCEG score recompute
- 2026-09-21 07:00 UTCEG score recompute
- 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-09-19 19:15 UTCEG score recompute
- 2026-09-19 07:15 UTCEG score recompute
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-09-17 19:37 UTCEG score recompute
- 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-09-16 17:52 UTCEG score recompute
- 2026-09-16 16:56 UTCEG score recompute
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-09-15 16:34 UTCEG score recompute
- 2026-09-11 22:24 UTCEG score recomputeFirst assessed: 8.5 HIGH
Related CVEs(same product + same CWE)
Frequently asked(5)
What is CVE-2026-59973?
When was the CVE record for CVE-2026-59973 published?
Is CVE-2026-59973 actively exploited?
What is the CVSS score of CVE-2026-59973?
How do I remediate CVE-2026-59973?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59973
Is Your Infrastructure Affected by CVE-2026-59973?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.