# CVE-2021-34598: Phoenix Contact: FL MGUARD lack of memory release in remote logging functionality

> Attackers can cause a denial of service in Phoenix Contact FL MGUARD firewalls by exhausting memory through remote logging.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 10 Nov 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-2mrx-q835-w93g

## What is CVE-2021-34598?

CVE-2021-34598 is a high-severity denial of service vulnerability in PHOENIX CONTACT FL MGUARD, published on 10 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Phoenix Contact FL MGUARD 1102 and 1105 in Versions 1.4.0, 1.4.1 and 1.5.0 the remote logging functionality is impaired by the lack of memory release for data structures from syslog-ng when remote logging is active

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2021-34598?

It affects 2 products.


Products: Phoenixcontact Fl Mguard 1102 Firmware, Phoenixcontact Fl Mguard 1105 Firmware.

## How do I fix CVE-2021-34598?

No fix has been published for CVE-2021-34598 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-34598 being exploited?

There is no known exploitation of CVE-2021-34598 in the wild and no public exploit code.

## Other vulnerabilities in PHOENIX CONTACT FL MGUARD

- [CVE-2021-34582](https://insights.sbomify.com/CVE-2021-34582/): Phoenix Contact: FL MGUARD XSS through web-based management and REST API (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-34598 and fix it if it is affected.

What it is: CVE-2021-34598 is a high-severity denial of service vulnerability in PHOENIX CONTACT FL MGUARD, published on 10 Nov 2021. 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-2021-34598 in the wild and no public exploit code.

Affected product: PHOENIX CONTACT FL MGUARD. 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-2021-34598/ (Markdown: https://insights.sbomify.com/CVE-2021-34598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-34598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-34598
- OSV: https://osv.dev/vulnerability/CVE-2021-34598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-34598/
Summaries are generated and may contain mistakes; the official description above is the record.