CVE-2026-58196

MEDIUMPre-NVD 4.74.7
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 4.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (35th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
4.7EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 4.7Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

ToolHive is a utility designed to simplify the deployment and management of Model Context Protocol (MCP) servers. Prior to 0.31.0, remote.Handler.Authenticate in pkg/auth/remote/handler.go invokes discovery.DetectAuthenticationFromServer in pkg/auth/discovery/discovery.go, whose host-side HTTP clients trust remote-server-controlled authentication discovery destinations, follow redirects without host or scheme restrictions, and do not consistently block private addresses. A malicious or compromised remote MCP server can place a resource_metadata URL in WWW-Authenticate for ParseWWWAuthenticate to extract, after which FetchResourceMetadata, OIDC issuer discovery, and well-known discovery can issue GET requests to link-local, RFC1918, or other internal services outside the server's container. The user connects to a server that the user intends to use, but the server controls the internal destination; this path does not depend on the separate NAT64 guard omission because the affected clients did not invoke IsPrivateIP, and it differs from the DCR resolver path that already refused redirects. The demonstrated primitive reaches internal-only HTTP services and reachability or error oracles, and can retrieve AWS metadata credentials where IMDSv1 accepts an unauthenticated GET, while IMDSv2 and GCP metadata prerequisites are not satisfied by the demonstrated request. This vulnerability is fixed in 0.31.0.

CVSS v3
4.7
EG Score
4.7MEDIUMmedium confidence
EG Risk
37
EG Risk 37/100

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 (value × EchelonGraph’s weight)
Severity47% × 45%
The EG Score, 4.7 of 10.
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
35th
KEV
Not listed

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.

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

July 15, 2026

Last Modified

September 30, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
Patch available. Sources: github_release, github, github_commit.
GitHub release Patch Available

v0.31.0

Patch available: stacklok/toolhive v0.31.0

https://github.com/stacklok/toolhive/releases/tag/v0.31.0
GitHub commit

commit 4ea6afb9048d (stacklok/toolhive)

Fix landed in stacklok/toolhive commit 4ea6afb9048d — awaiting tagged release

https://github.com/stacklok/toolhive/commit/4ea6afb9048ddec1d56875fa9e0da36d65c15966
GitHub advisoryMentions a patch (unverified)

SSRF in remote MCP server authentication discovery (host-side, bypasses container isolation) · Advisory · stacklok/toolhive · GitHub

https://github.com/stacklok/toolhive/security/advisories/GHSA-pr64-jmmf-jp54

Vendor Advisories for CVE-2026-58196(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/stacklok/toolhive—
  • every version up to 0.31.0: fixed in 0.31.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 37× 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.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  3. 2026-10-12 15:53 UTCEG score recompute
  4. 2026-10-11 19:36 UTCEG score recompute
  5. 2026-10-11 16:52 UTCEG score recompute
  6. 2026-10-11 14:14 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  16. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  18. 2026-09-30 18:11 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  20. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  22. 2026-09-28 08:40 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 34th percentile
Show 16 more
  1. 2026-09-24 08:45 UTCEG score recompute
  2. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  3. 2026-09-23 03:12 UTCEG score recompute
  4. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  6. 2026-09-18 04:42 UTCEG score recompute
  7. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  9. 2026-09-15 18:36 UTCEG score recompute
  10. 2026-09-15 18:14 UTCEG score recompute
  11. 2026-09-15 16:35 UTCEG score recompute
  12. 2026-09-15 16:02 UTCMITRE cvelistV5severity → MEDIUM
  13. 2026-07-31 00:48 UTCEG score recompute
  14. 2026-07-26 11:28 UTCEG score recompute
  15. 2026-07-23 03:20 UTCEG score recompute
  16. 2026-07-15 23:54 UTCEG score recompute

Related CVEs(same product + same CWE)

Same product

2 shown

Go:github.com/stacklok/toolhive

Frequently asked(5)

What is CVE-2026-58196?
CVE-2026-58196 is a medium-severity vulnerability; its CVE record was published on July 15, 2026. ToolHive is a utility designed to simplify the deployment and management of Model Context Protocol (MCP) servers. Prior to 0.31.0, remote.Handler.Authenticate in pkg/auth/remote/handler.go invokes discovery.DetectAuthenticationFromServer in pkg/auth/discovery/discovery.go, whose host-side HTTP…
When was the CVE record for CVE-2026-58196 published?
The CVE record for CVE-2026-58196 was published on July 15, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 30, 2026; the record at its source may have been updated since.
Is CVE-2026-58196 actively exploited?
CVE-2026-58196 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (35th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-58196?
CVE-2026-58196 has a CVSS base score of 4.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-58196?
A fix for CVE-2026-58196 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-58196 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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