# CVE-2023-28984: Junos OS: QFX Series: The PFE may crash when a lot of MAC addresses are being learned and aged

> An adjacent attacker can cause a denial of service on Juniper QFX switches by triggering a use-after-free condition during MAC address learning and aging.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Apr 2023
- **Updated:** 5 Feb 2025
- **Also known as:** GHSA-vx3w-5gr7-767w

## What is CVE-2023-28984?

CVE-2023-28984 is a medium-severity use after free vulnerability in Juniper Junos, published on 17 Apr 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Use After Free vulnerability in the Layer 2 Address Learning Manager (l2alm) of Juniper Networks Junos OS on QFX Series allows an adjacent attacker to cause the Packet Forwarding Engine to crash and restart, leading to a Denial of Service (DoS). The PFE may crash when a lot of MAC learning and aging happens, but due to a Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) that is outside the attackers direct control. This issue affects: Juniper Networks Junos OS versions prior to 19.4R3-S10 on QFX Series; 20.2 versions prior to 20.2R3-S7 on QFX Series; 20.3 versions prior to 20.3R3-S6 on QFX Series; 20.4 versions prior to 20.4R3-S5 on QFX Series; 21.1 versions prior to 21.1R3-S4 on QFX Series; 21.2 versions prior to 21.2R3-S3 on QFX Series; 21.3 versions prior to 21.3R3-S3 on QFX Series; 21.4 versions prior to 21.4R3 on QFX Series; 22.1 versions prior to 22.1R3 on QFX Series; 22.2 versions prior to 22.2R2 on QFX Series.

Weakness: CWE-416 (Use After Free), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2023-28984?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2023-28984?

No fix has been published for CVE-2023-28984 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28984 being exploited?

There is no known exploitation of CVE-2023-28984 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-2023-28984 and fix it if it is affected.

What it is: CVE-2023-28984 is a medium-severity use after free vulnerability in Juniper Junos, published on 17 Apr 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-2023-28984 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-2023-28984/ (Markdown: https://insights.sbomify.com/CVE-2023-28984/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28984
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28984
- OSV: https://osv.dev/vulnerability/CVE-2023-28984

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28984/
Summaries are generated and may contain mistakes; the official description above is the record.