CVE-2026-125271
AWS API MCP Server Security Policy Bypass via Incorrect Operation Name Normalization
Description
Incorrect normalization of operation names in the custom security policy enforcement in awslabs aws-api-mcp-server before 1.5.1 might allow an actor to execute AWS API operations across AWS services that the operator's security policy was configured to deny or require elicitation for, via calls to operations whose names contain consecutive capital letters. To remediate this issue, users should upgrade to version 1.5.1.
INFO
Published Date :
Nov. 10, 2026, 5:17 p.m.
Last Modified :
Nov. 10, 2026, 5:17 p.m.
Remotely Exploit :
No
Source :
ff89ba41-3aa1-4d27-914a-91399e9639e5
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 4.0 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 4.0 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 |
Solution
- Upgrade to version 1.5.1.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-125271.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-125271 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-125271
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-125271 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-125271 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by ff89ba41-3aa1-4d27-914a-91399e9639e5
Nov. 10, 2026
Action Type Old Value New Value Added Description Incorrect normalization of operation names in the custom security policy enforcement in awslabs aws-api-mcp-server before 1.5.1 might allow an actor to execute AWS API operations across AWS services that the operator's security policy was configured to deny or require elicitation for, via calls to operations whose names contain consecutive capital letters. To remediate this issue, users should upgrade to version 1.5.1. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/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 Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-1025 Added CWE CWE-863 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/125xxx/CVE-2026-125271.json">CVE-2026-125271</a> Added Reference https://aws.amazon.com/security/security-bulletins/2026-176-aws/ Added Reference https://github.com/awslabs/mcp/security/advisories/GHSA-4wq9-grf3-qg2p Added Reference https://pypi.org/project/awslabs.aws-api-mcp-server/1.5.1/