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Fencer Vulns
critical 9.1

CVE-2026-11720 json

Path Traversal in googleapis/mcp-toolbox HTTP Tool URL Builder

published 2026-06-29 4 mo ago modified 2026-10-25 14 d ago also GHSA-vwxw-jrg6-9jxv , GO-2026-6411 , EUVD-2026-40146

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

A path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox.

When constructing downstream API requests, the URL builder substitutes user-controlled pathParams into the configured tool path and parses the resulting string as a relative URL. While it checks that the input does not alter the scheme, host, or user info, it relies on ResolveReference for the final URL resolution. Because dot segments (../) are normalized during this resolution step, an attacker can supply path parameters containing directory traversal sequences to escape the operator-configured path scope. This allows the client to coerce the toolbox into making requests to unintended endpoints on the same target host while forwarding the toolbox's configured credentials (e.g., bypassing a restricted path like /api/v1/users/{{.id}} to reach /admin/secrets).

Patch / fix

  • go github.com/googleapis/mcp-toolbox 1.3.0
  • Google MCP Toolbox for Databases (googleapis/mcp-toolbox) 1.3.0
  • govulncheck-vulndb SLES 16.0, SLES for SAP applications 16.0 0.0.20260916T180043-160000.1.1

suse advisories SUSE-SU-2026:23855-1SUSE-SU-2026:23863-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260916T180043-160000.1.1

opensuse advisories openSUSE-SU-2026:21897-1

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/googleapis/mcp-toolbox
<1.3.0
1.3.0

Affected products

  • Google MCP Toolbox for Databases (googleapis/mcp-toolbox)

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.