EUVD-2026-31697
GHSA-8744-whr8-7m8p
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/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
Primary rating from Vendor (VulDB) · only source for this CVE.
CVSS VectorVendor: VulDB
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/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
Lifecycle Timeline
3DescriptionCVE.org
A vulnerability was identified in debugmcp mcp-debugger up to 0.20.0. Impacted is the function handleGetSourceContext of the file src/server.ts. The manipulation leads to path traversal. The attack is possible to be carried out remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.
AnalysisAI
Path traversal in debugmcp mcp-debugger through version 0.20.0 enables authenticated remote attackers with low-privilege access to read arbitrary files outside the intended directory via the handleGetSourceContext function in src/server.ts. Impact is restricted to limited confidentiality exposure on the vulnerable system (CVSS VC:L) with no integrity or availability consequence, yielding a CVSS 4.0 score of 2.1. A public proof-of-concept exploit exists on GitHub, though the EPSS score remains at 0.04% (12th percentile) and the issue is absent from the CISA KEV catalog, indicating exploitation has not been observed at meaningful scale. The vendor did not respond to responsible disclosure, meaning no official patch is available.
Technical ContextAI
The affected component is the handleGetSourceContext function within src/server.ts of the mcp-debugger package (CPE: cpe:2.3:a:debugmcp:mcp-debugger:*:*:*:*:*:*:*:*), a Model Context Protocol (MCP) debugging server used in MCP-based developer tooling. CWE-22 (Path Traversal) identifies the root cause class: insufficient sanitization or canonicalization of user-supplied file path input. The handleGetSourceContext function reads source file contents to provide debugging context, meaning it processes file path parameters that an attacker can manipulate with directory traversal sequences (e.g., ../../) to escape the intended working directory and reach arbitrary files readable by the server process. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L) confirms network delivery with low attack complexity and no special attack preconditions beyond authentication.
RemediationAI
No vendor-released patch has been identified at time of analysis - the vendor did not respond to responsible disclosure, so no fix version can be cited. Organizations should monitor the mcp-debugger project repository for any future patched release and upgrade immediately upon availability. As immediate compensating controls, restrict access to the mcp-debugger server to explicitly trusted, low-privilege users only and avoid exposing it over untrusted networks or the public internet; this directly addresses the network attack vector (AV:N) and authentication prerequisite (PR:L). Implement server-side path canonicalization and strict allowlisting at the infrastructure layer, for example via a reverse proxy rule blocking requests containing ../ or URL-encoded traversal sequences - note this control can be bypassed by alternative encoding and is not a substitute for a code-level fix. Consider removing or disabling mcp-debugger from any environment where the server process has read access to sensitive files outside its intended working directory. Additional context is available at https://vuldb.com/vuln/365448 and https://nvd.nist.gov/vuln/detail/CVE-2026-9467.
Same weakness CWE-22 – Path Traversal
View allSame technique Path Traversal
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External POC / Exploit Code
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