CVE-2026-125271 AWS API MCP Server Security Policy Bypass via Incorrect Operation Name Normalization
High 8.5
Published
Updated
Check this codebase for CVE-2026-125271 and fix it if it is affected.
What it is: CVE-2026-125271 is a high-severity vulnerability in aws-api-mcp-server, published on 10 Nov 2026.
Exploitation: There is no known exploitation of CVE-2026-125271 in the wild and no public exploit code.
Affected product: aws-api-mcp-server. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-125271/ (Markdown: https://insights.sbomify.com/CVE-2026-125271/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-125271?
CVE-2026-125271 is a high-severity vulnerability in aws-api-mcp-server, published on 10 Nov 2026.
Official 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.
Which versions are affected by CVE-2026-125271?
How do I fix CVE-2026-125271?
No fix has been published for CVE-2026-125271 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-125271 being exploited?
There is no known exploitation of CVE-2026-125271 in the wild and no public exploit code.