Path filters that do not filter: CVE-2026-57441 and CVE-2026-57442 in MCPVault

MCPVault software restricts which directories a language model can access. Two security advisories have revealed weaknesses in how MCPVault enforces those restrictions. The first, CVE-2026-57441, arises from a case-insensitive string comparison used to determine allowed paths. On a system where file system case differs from the comparison, paths with case variants of restricted directories, such as .git or node_modules, pass through unchecked.

Consequently, the MCPVault restriction fails to take effect. The second advisory, CVE-2026-57442, concerns a deny list anchored at the root of the file system tree. This design allows nested restricted directories to bypass the check, as the pattern only matches at the root level. Both advisories underscore the importance of comparing paths after they've been resolved to their absolute, canonical form, rather than using a string-based comparison which can be manipulated by the underlying file system.

To mitigate these risks, users should upgrade to the versions specified in the advisories, limit the scope of the boundary, and run the server as a user with restricted privileges. Using read-only mode where available further reduces the potential impact of these vulnerabilities.