# CVE-2017-7909: Auth bypass in Advantech B+B SmartWorx MESR901

> Attackers can bypass client-side JavaScript authentication to access restricted web pages on Advantech industrial routers.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 May 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-63p9-9p5p-v46f

## What is CVE-2017-7909?

CVE-2017-7909 is a critical authentication bypass vulnerability in Advantech B+B SmartWorx MESR901, published on 6 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A Use of Client-Side Authentication issue was discovered in Advantech B+B SmartWorx MESR901 firmware versions 1.5.2 and prior. The web interface uses JavaScript to check client authentication and redirect unauthorized users. Attackers may intercept requests and bypass authentication to access restricted web pages.

Weakness: CWE-287 (Improper Authentication), CWE-603 (Use of Client-Side Authentication)

## Which versions are affected by CVE-2017-7909?

It affects 1 product.


Products: Advantech B\+b Smartworx Mesr901 Firmware.

## How do I fix CVE-2017-7909?

No fix has been published for CVE-2017-7909 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-7909 being exploited?

There is no known exploitation of CVE-2017-7909 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-7909 and fix it if it is affected.

What it is: CVE-2017-7909 is a critical authentication bypass vulnerability in Advantech B+B SmartWorx MESR901, published on 6 May 2017. 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-2017-7909 in the wild and no public exploit code.

Affected product: Advantech B+B SmartWorx MESR901. 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-2017-7909/ (Markdown: https://insights.sbomify.com/CVE-2017-7909/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7909
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7909
- OSV: https://osv.dev/vulnerability/CVE-2017-7909

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-7909/
Summaries are generated and may contain mistakes; the official description above is the record.