AWS API MCP File Access Restriction Bypass
Improper Protection of Alternate Path exists in the no-access and workdir feature of the AWS API MCP Server versions >= 0.2.14 and < 1.3.9 on all platforms may allow the bypass of intended file access restriction and expose arbitrary local file contents in the MCP client application context. To remediate this issue, users should upgrade to version 1.3.9.
- Published
- Mar 16, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 7th percentile
- CWE
- CWE-424
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Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 27 / 40 · 6.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · AMZN
- 5.5
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| amazon | aws api mcp server | cpe:2.3:a:amazon:aws_api_mcp_server |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- amazon aws api mcp server0.2.14 and later · before 1.3.9
Versions reported by the vendor
Affected version ranges reported by the assigning authority (AMZN). Independent of NVD's CPE analysis and usually ahead of it.
AWS AWS API MCP Server
- 0.2.14 and later · before 1.3.9affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| PyPI | awslabs-aws-api-mcp-server | from 0.2.14 · before 1.3.9 | 1.3.9 |
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| AWS AWS API MCP Server | 1.3.9 · description | Vendor (CNA) |
| PyPI:awslabs-aws-api-mcp-server | 1.3.9 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- P
- Scope
- X
Weakness class (CWE)
CWE-424 · Improper Protection of Alternate PathCVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- aws.amazon.com/security/security-bulletins/2026-007-AWS/
- pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.