vulnerability / NVI-00009026 / Revision 2
mcp-sanitizer: File Path Sanitizer Permits Arbitrary User-Home Absolute Paths
GitHub lists this reviewed advisory for mcp-sanitizer. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
mcp-sanitizer
source listed< 1.4.0
## File Path Sanitizer Permits Arbitrary User-Home Absolute Paths ### Summary `mcp-sanitizer` v1.3.3 explicitly whitelists `/home/` and `/Users/` as allowed absolute path prefixes in its file path validation logic (`src/utils/validation-utils.js:188-196`). As a result, paths such as `/home/alice/.ssh/id_rsa` and `/home/alice/.aws/credentials` pass through `sanitizer.sanitize()` with `blocked=false`, even though they point to highly sensitive files outside any configured safe root. Any consumer application that trusts the sanitized path and passes it to a filesystem read/write operation (e.g., `fs.readFile`) will expose arbitrary user-home directory files to an unauthenticated network attacker. Dynamic reproduction confirmed exfiltration of a simulated SSH private key and AWS credentials via a single HTTP POST request. ### Details The vulnerability resides in the `validateFilePath` function inside `src/utils/validation-utils.js`. When an absolute path falls outside the configured safe root directories, the function performs a secondary check against a hardcoded allowlist: ```js // src/utils/validation-utils.js:188-196 if (!isInSafeLocation && path.isAbsolute(normalizedPath)) {
mcp-sanitizer
source listedSEMVER: introduced 0; fixed 1.4.0
## File Path Sanitizer Permits Arbitrary User-Home Absolute Paths ### Summary `mcp-sanitizer` v1.3.3 explicitly whitelists `/home/` and `/Users/` as allowed absolute path prefixes in its file path validation logic (`src/utils/validation-utils.js:188-196`). As a result, paths such as `/home/alice/.ssh/id_rsa` and `/home/alice/.aws/credentials` pass through `sanitizer.sanitize()` with `blocked=false`, even though they point to highly sensitive files outside any configured safe root. Any consumer application that trusts the sanitized path and passes it to a filesystem read/write operation (e.g., `fs.readFile`) will expose arbitrary user-home directory files to an unauthenticated network attacker. Dynamic reproduction confirmed exfiltration of a simulated SSH private key and AWS credentials via a single HTTP POST request. ### Details The vulnerability resides in the `validateFilePath` function inside `src/utils/validation-utils.js`. When an absolute path falls outside the configured safe root directories, the function performs a secondary check against a hardcoded allowlist: ```js // src/utils/validation-utils.js:188-196 if (!isInSafeLocation && path.isAbsolute(normalizedPath)) {
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
- vendor patch
The original advisory lists fixed boundaries 1.4.0 for mcp-sanitizer. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-7w82-6f9j-v9jp ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-7w82-6f9j-v9jp ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.