# CVE-2023-44193: Use after free in Junos OS

> A local low-privileged attacker can cause a denial of service by triggering a use-after-free crash in the Packet Forwarding Engine when specific LDP commands are run with CFM enabled.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2023
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-3vfv-wc96-x87r

## What is CVE-2023-44193?

CVE-2023-44193 is a medium-severity use after free vulnerability in Juniper Junos, published on 12 Oct 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An Improper Release of Memory Before Removing Last Reference vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows a local, low privileged attacker to cause an FPC crash, leading to Denial of Service (DoS).

On all Junos MX Series with MPC1 - MPC9, LC480, LC2101, MX10003, and MX80, when Connectivity-Fault-Management (CFM) is enabled in a VPLS scenario, and a specific LDP related command is run, an FPC will crash and reboot. Continued execution of this specific LDP command can lead to sustained Denial of Service condition.

This issue affects:

Juniper Networks Junos OS on MX Series:

  *  All versions prior to 20.4R3-S7;
  *  21.1 versions prior to 21.1R3-S5;
  *  21.2 versions prior to 21.2R3-S4;
  *  21.3 versions prior to 21.3R3-S4;
  *  21.4 versions prior to 21.4R3-S3;
  *  22.1 versions prior to 22.1R3-S1;
  *  22.2 versions prior to 22.2R2-S1, 22.2R3;
  *  22.3 versions prior to 22.3R1-S2, 22.3R2.

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

## Which versions are affected by CVE-2023-44193?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2023-44193?

No fix has been published for CVE-2023-44193 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-44193 being exploited?

There is no known exploitation of CVE-2023-44193 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos

- [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild)
- [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild)
- [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild)
- [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)
- [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-44193 and fix it if it is affected.

What it is: CVE-2023-44193 is a medium-severity use after free vulnerability in Juniper Junos, published on 12 Oct 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-44193 in the wild and no public exploit code.

Affected product: Juniper Junos. 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-2023-44193/ (Markdown: https://insights.sbomify.com/CVE-2023-44193/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-44193
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-44193
- OSV: https://osv.dev/vulnerability/CVE-2023-44193

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-44193/
Summaries are generated and may contain mistakes; the official description above is the record.