VulnerabilityPublished 2 Nov 2026

CVE-2026-116635: aws-serverless-mcp-server · Relative Path Traversal

Affects aws-serverless-mcp-serverSource CVE Database V5

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Not known to be exploited · CVSS 6.1 Medium : upgrade to 0.2.1 when convenient.

Data as of 2 Nov 2026, 21:58 UTC

CVSS 3.1 base score

6.1Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (AMZN)	CVSS 3.1	6.1
CNA (AMZN)	CVSS 4.0	6.9

Patch: Available – fixed in 0.2.1

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade aws-serverless-mcp-server and awslabs-aws-serverless-mcp-server to 0.2.1.

Affected software

Product	Affected	Fixed in
AWSaws-serverless-mcp-server	Affected <0.2.1	Fixed in 0.2.1
PyPIawslabs-aws-serverless-mcp-server`pkg:pypi/awslabs-aws-serverless-mcp-server`Other threats	Affected <0.2.1	Fixed in 0.2.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should upgrade aws-serverless-mcp-server to version 0.2.1 or later, where this vulnerability is fixed. Since this is a cloud service managed by AWS, the vendor handles remediation for the cloud-hosted service. Check the AWS security bulletin at https://aws.amazon.com/security/security-bulletins/2026-164-aws/ for official guidance and confirmation of patch status.

Description

CVE-2026-116635 is a relative path traversal vulnerability in the AWS Serverless MCP Server (aws-serverless-mcp-server) before version 0.2.1. It allows an attacker who can influence the MCP agent to read JSON files outside the intended deployment status directory and, if write access is enabled, to create or overwrite JSON files outside that directory. The vulnerability arises from improper limitation of pathname inputs, which can be exploited using directory traversal sequences or absolute paths in the project name input. AWS has released version 0.2.1 to address this issue.

Reports on CVE-2026-116635

CVE-2026-116635: Improper limitation of a pathname to a restricted directory in the deployment status component of the AWS Serverless MCP ServerAWS Security Bulletins2026-11-02

Impact

An attacker able to influence the MCP agent can read sensitive JSON files outside the intended directory, potentially exposing confidential data. If write access is enabled, the attacker can also create or overwrite JSON files outside the deployment status directory, impacting data integrity. There is no impact on availability. The CVSS 3.1 score is 6.1 (medium severity), reflecting high confidentiality impact, low integrity impact, and no availability impact.

Summary

The vulnerability CVE-2026-116635 affects the deployment status component of aws-serverless-mcp-server versions prior to 0.2.1. Due to improper validation of pathname inputs, an attacker with influence over the MCP agent can perform relative path traversal to access or modify JSON files outside the designated deployment status directory. This can lead to unauthorized disclosure of sensitive information (confidentiality impact) and limited integrity impact by overwriting files if write permissions are enabled. The flaw is remediated in version 0.2.1.

CWE-23Relative Path Traversal (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
Operation · Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Relative Path Traversal (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-36Absolute Path Traversal (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize absolute path sequences such as "/abs/path" that can resolve to a location that is outside of that directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
Operation · Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Absolute Path Traversal (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

Reports on CVE-2026-116635

AI analysisMachine-generated, updated 2 Nov 2026, 21:44 UTC

WeaknessesCWE-23, CWE-36

Technical details

References

Community reviews

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