# CVE-2026-70553: MaxSite CMS Unauthenticated RCE via Install Endpoint

> Unauthenticated attackers can achieve persistent remote code execution by injecting PHP code into the configuration file via the install endpoint.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-32g8-v8qx-8c7w

## What is CVE-2026-70553?

CVE-2026-70553 is a critical code injection vulnerability in MaxSite CMS, published on 4 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

MaxSite CMS contains a remote code execution vulnerability that allows unauthenticated attackers to inject arbitrary PHP code into the application configuration file by submitting crafted POST requests to the install endpoint after installation is complete. Attackers can supply a malicious db_dbprefix value containing a single quote to break out of a PHP string literal in application/config/database.php, appending attacker-controlled PHP statements that are executed by the web server on every subsequent request, resulting in persistent unauthenticated remote code execution as the web-server process user.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-70553?


## How do I fix CVE-2026-70553?

No fix has been published for CVE-2026-70553 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-70553 being exploited?

There is no known exploitation of CVE-2026-70553 in the wild and no public exploit code.

Public exploit code:

- https://github.com/woshidashabi1126/CVE-2026-70553-PoC (github_poc): https://github.com/woshidashabi1126/CVE-2026-70553-PoC

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-70553 and fix it if it is affected.

What it is: CVE-2026-70553 is a critical code injection vulnerability in MaxSite CMS, published on 4 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-70553 in the wild and no public exploit code.

Affected product: MaxSite CMS. 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-2026-70553/ (Markdown: https://insights.sbomify.com/CVE-2026-70553/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-70553
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-70553
- OSV: https://osv.dev/vulnerability/CVE-2026-70553

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-70553/
Summaries are generated and may contain mistakes; the official description above is the record.