# CVE-2026-87911: Command injection in AWS Labs postgres MCP Server

> An attacker can execute OS commands on the host by bypassing read-only SQL validation in the PostgreSQL MCP server.

- **Severity:** Critical 9.0 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 9 Sep 2026
- **Updated:** 10 Sep 2026

## What is CVE-2026-87911?

CVE-2026-87911 is a critical command injection vulnerability in AWS Labs postgres MCP Server, published on 9 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

An OS command injection weakness in the read-only enforcement of the SQL validation component in Amazon awslabs postgres-mcp-server before 1.1.7 might allow an unauthenticated actor to execute operating system commands on the host of a self-managed PostgreSQL server by placing a crafted COPY ... TO PROGRAM statement into content that is processed when an authenticated user interacts with the MCP server in its default read-only mode.

To remediate this issue, users should upgrade to version 1.1.7 or later.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-87911?


## How do I fix CVE-2026-87911?

No fix has been published for CVE-2026-87911 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-87911 being exploited?

There is no known exploitation of CVE-2026-87911 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-87911 and fix it if it is affected.

What it is: CVE-2026-87911 is a critical command injection vulnerability in AWS Labs postgres MCP Server, published on 9 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-87911 in the wild and no public exploit code.

Affected product: AWS Labs postgres 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-2026-87911/ (Markdown: https://insights.sbomify.com/CVE-2026-87911/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-87911
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87911
- OSV: https://osv.dev/vulnerability/CVE-2026-87911

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-87911/
Summaries are generated and may contain mistakes; the official description above is the record.