MCPyATS CVE-2026-19338

Q: What is the CVSS score of CVE-2026-19338?

CVE-2026-19338 has a CVSS 4.0 base score of 1.9 (Low). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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. EPSS exploitation probability: 0.1%.

EUVD-2026-54907 LOW

Path Traversal (CWE-22)

2026-08-09 VulDB

GHSA-q9qj-38cq-3792

Path Traversal Mcpyats

1.9

CVSS 4.0 · Vendor: VulDB

Severity by source

Vendor (VulDB) PRIMARY

1.9 MEDIUM

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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

vuln.today AI

5.3 MEDIUM

Local attack vector and low-privilege requirement reflect that exploitation demands an existing authenticated shell session; no scope change as impacts stay within the vulnerable system.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

Primary rating from Vendor (VulDB).

CVSS VectorVendor: VulDB

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Severity Changed

Aug 09, 2026 - 07:22 NVD

MEDIUM LOW

CVSS changed

Aug 09, 2026 - 07:22 NVD

4.8 (MEDIUM) 1.9 (LOW)

Analysis Generated

Aug 09, 2026 - 06:46 vuln.today

DescriptionCVE.org

A vulnerability was identified in automateyournetwork MCPyATS up to 0.1.4. The affected element is the function processGenerateRequest of the file mcp_servers/mermaid/index.ts of the component generate_mermaid_markdown. The manipulation of the argument folder/name leads to path traversal. The attack must be carried out locally.

AnalysisAI

Path traversal in MCPyATS up to version 0.1.4 enables a local low-privileged attacker to escape the intended working directory by supplying crafted folder or name arguments to the processGenerateRequest function within the generate_mermaid_markdown MCP tool. The CVSS 4.0 vector (AV:L/PR:L/E:P) confirms local-only exploitation requiring low privileges, with a proof-of-concept publicly disclosed via VulDB. This CVE is not listed in CISA KEV, indicating no confirmed active exploitation in the wild at time of analysis.

Technical ContextAI

MCPyATS is an open-source Model Context Protocol (MCP) server built on Cisco's pyATS network automation framework, published by automateyournetwork on GitHub. The vulnerable component is the Mermaid diagram generation sub-server, implemented in TypeScript at mcp_servers/mermaid/index.ts. The processGenerateRequest function accepts user-controlled folder and name parameters and constructs filesystem paths without adequately sanitizing traversal sequences such as ../. CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) identifies this root cause class: the application trusts caller-supplied path components and resolves them relative to an assumed safe base directory, allowing callers to reference files anywhere the process has OS-level read or write access.

RemediationAI

Monitor the vendor's GitHub repository at https://github.com/automateyournetwork/MCPyATS/ and the issue tracker entry at https://github.com/automateyournetwork/MCPyATS/issues/22 for a patched release beyond version 0.1.4; upgrade to that version once available. No vendor-released patch with an exact fix version was identified at time of analysis. As an interim compensating control, restrict OS-level access to the host running MCPyATS so that only fully trusted accounts can execute the process or invoke the generate_mermaid_markdown tool - this trades off operational convenience but eliminates untrusted-caller risk. Additionally, operators managing their own deployments can apply server-side input validation on the folder and name parameters in processGenerateRequest, rejecting any argument containing .. or absolute path characters before path resolution occurs; this is a targeted fix with no known functional side effects for legitimate use cases.