CVE-2026-54561

MCP Memory Keeper is an MCP server for persistent context management in AI coding assistants. Prior to 0.13.0, context_import in src/index.ts passes the caller-controlled filePath directly to fs.readFileSync without restricting the path to an export directory. An MCP client, including an LLM agent induced to call the tool, can use ../ traversal or an absolute path to target any file readable by the server process. A valid JSON file is parsed and imported into the caller's session, allowing its full contents to be retrieved through context_get or context_export, while JSON.parse errors for non-JSON files can return leading file bytes in a SyntaxError message. The two disclosure modes can expose other exported sessions, JSON credentials or service-account files, environment files, and portions of SSH keys or other local files. This issue is fixed in version 0.13.0.

MCP Memory Keeper is an MCP server for persistent context management in AI coding assistants. Prior to 0.13.0, context_import in src/index.ts passes the caller-controlled filePath directly to fs.readFileSync without restricting the path to an export directory. An MCP client, including an LLM agent induced to call the tool, can use ../ traversal or an absolute path to target any file readable by the server process. A valid JSON file is parsed and imported into the caller's session, allowing its full contents to be retrieved through context_get or context_export, while JSON.parse errors for non-JSON files can return leading file bytes in a SyntaxError message. The two disclosure modes can expose other exported sessions, JSON credentials or service-account files, environment files, and portions of SSH keys or other local files. This issue is fixed in version 0.13.0.

Impact

context_import passed the caller-supplied filePath directly to fs.readFileSync with no path confinement. A malicious MCP client — or an LLM agent that is prompt-injected into calling the tool — could point filePath at any file readable by the server process, outside any session or export directory:

• Full disclosure (JSON files): a valid-JSON target (e.g. another user's exported session, or a *.json credential / service-account file) is parsed and imported into the caller's session, then retrievable verbatim via context_get / context_export.
• Partial disclosure (any file): for a non-JSON target (e.g. /etc/passwd, an SSH key, a .env), JSON.parse throws and V8 includes a snippet of the file's leading bytes in the SyntaxError message, which was returned verbatim to the caller.

Both ../ traversal and absolute paths worked — there was no path confinement of any kind.

In a typical MCP deployment the server runs on the developer's machine, so the reachable set includes other users' exported memory sessions, JSON credential/config files, and (in leading-bytes form) .env files, SSH keys, and /etc/passwd. The trigger is a tool argument, so the realistic threat model is an LLM agent prompt-injected into calling context_import, or any MCP client connected to the server.

Patches

Fixed in 0.13.0 (PR #36):

• Imports are confined to a server-owned exports directory (<DATA_DIR>/exports, overridable via MEMORY_KEEPER_EXPORT_DIR), resolved with realpathSync. ../ traversal, absolute paths outside the directory, and symlink escapes are all rejected.
• File read and JSON.parse are separate operations; read/parse failures return a generic message and never echo file bytes (the SyntaxError-message leak is gone). The database-write path is likewise generic.
• An E2E security regression suite covers the reported arbitrary-read and traversal vectors, plus symlink escape, the directory-prefix boundary, and a no-existence-oracle check.

Workarounds

Upgrade to >= 0.13.0. There is no configuration-only workaround for affected versions.

Resources

• Report: GitHub issue #35
• Fix: PR #36

Credit

Reported by Zhihao Zhang (@mcfly-zzh).

MCP Memory Keeper is an MCP server for persistent context management in AI coding assistants. Prior to 0.13.0, context_import in src/index.ts passes the caller-controlled filePath directly to fs.readFileSync without restricting the path to an export directory. An MCP client, including an LLM agent induced to call the tool, can use ../ traversal or an absolute path to target any file readable by the server process. A valid JSON file is parsed and imported into the caller's session, allowing its full contents to be retrieved through context_get or context_export, while JSON.parse errors for non-JSON files can return leading file bytes in a SyntaxError message. The two disclosure modes can expose other exported sessions, JSON credentials or service-account files, environment files, and portions of SSH keys or other local files. This issue is fixed in version 0.13.0.

MCP Memory Keeper is an MCP server for persistent context management in AI coding assistants. Prior to 0.13.0, context_import in src/index.ts passes the caller-controlled filePath directly to fs.readFileSync without restricting the path to an export directory. An MCP client, including an LLM agent induced to call the tool, can use ../ traversal or an absolute path to target any file readable by the server process. A valid JSON file is parsed and imported into the caller's session, allowing its full contents to be retrieved through context_get or context_export, while JSON.parse errors for non-JSON files can return leading file bytes in a SyntaxError message. The two disclosure modes can expose other exported sessions, JSON credentials or service-account files, environment files, and portions of SSH keys or other local files. This issue is fixed in version 0.13.0.

Impact

context_import passed the caller-supplied filePath directly to fs.readFileSync with no path confinement. A malicious MCP client — or an LLM agent that is prompt-injected into calling the tool — could point filePath at any file readable by the server process, outside any session or export directory:

• Full disclosure (JSON files): a valid-JSON target (e.g. another user's exported session, or a *.json credential / service-account file) is parsed and imported into the caller's session, then retrievable verbatim via context_get / context_export.
• Partial disclosure (any file): for a non-JSON target (e.g. /etc/passwd, an SSH key, a .env), JSON.parse throws and V8 includes a snippet of the file's leading bytes in the SyntaxError message, which was returned verbatim to the caller.

Both ../ traversal and absolute paths worked — there was no path confinement of any kind.

In a typical MCP deployment the server runs on the developer's machine, so the reachable set includes other users' exported memory sessions, JSON credential/config files, and (in leading-bytes form) .env files, SSH keys, and /etc/passwd. The trigger is a tool argument, so the realistic threat model is an LLM agent prompt-injected into calling context_import, or any MCP client connected to the server.

Patches

Fixed in 0.13.0 (PR #36):

• Imports are confined to a server-owned exports directory (<DATA_DIR>/exports, overridable via MEMORY_KEEPER_EXPORT_DIR), resolved with realpathSync. ../ traversal, absolute paths outside the directory, and symlink escapes are all rejected.
• File read and JSON.parse are separate operations; read/parse failures return a generic message and never echo file bytes (the SyntaxError-message leak is gone). The database-write path is likewise generic.
• An E2E security regression suite covers the reported arbitrary-read and traversal vectors, plus symlink escape, the directory-prefix boundary, and a no-existence-oracle check.

Workarounds

Upgrade to >= 0.13.0. There is no configuration-only workaround for affected versions.

Resources

• Report: GitHub issue #35
• Fix: PR #36

Credit

Reported by Zhihao Zhang (@mcfly-zzh).