MCPVault: PathFilter restricted-directory deny-list bypass via case and trailing dot/space equivalence

published 2026-06-18 4 mo ago modified 2026-09-30 39 d ago also GHSA-j99q-93c9-h869 , EUVD-2026-79125

cvss: 8.4; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits: 0; none known

MCPVault is a lightweight Model Context Protocol server for safe access to files in an Obsidian vault. Prior to 0.11.4, PathFilter in src/pathfilter.ts compiles restricted-directory patterns case-sensitively and compares paths without canonicalizing filesystem-equivalent segment names. On case-insensitive macOS and Windows filesystems, case variants of .git, .obsidian, or node_modules pass both isAllowed() and isAllowedForListing() even though the operating system opens the restricted directory, and Windows trailing dots or spaces provide the same bypass. An attacker who influences a path selected by an AI agent can use the bypass in read, write, move, search, or listing operations to expose or modify sensitive repository and Obsidian metadata. Vault-root .. containment is not affected. This issue is fixed in version 0.11.4.

Patch / fix

fixed in 1 links 2

npm @bitbonsai/mcpvault 0.11.4

github.com/bitbonsai/mcpvault@0adb439 commit
github.com/bitbonsai/mcpvault@b9ea91a commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 54 d ago (2026-09-15)

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.4	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
CNA	4.0	8.4	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:L/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

Affected packages

ecosystem	package	affected	fixed in
npm	@bitbonsai/mcpvault	<0.11.4	0.11.4

Affected products

bitbonsai mcpvault

Classification

Weakness

CWE-41 Improper Resolution of Path Equivalence
CWE-178 Improper Handling of Case Sensitivity

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.

Summary