# What is CVE-2023-44189?

> CVE-2023-44189 is a medium-severity flaw (CVSS 5.4) in Junos OS Evolved from Juniper, published on 11 October 2023. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 0.2%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2023-44189

## At a glance

- **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle.
- **Precursor Intelligence risk score:** 19 out of 100 (Info); action: Track. Kept up to date as the evidence changes.
- **Severity:** Medium (CVSS 5.4 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 0.2% (latest exploit-likelihood forecast)
- **Published:** 11 October 2023
- **Record last updated:** 19 October 2023
- **Main product:** Junos OS Evolved from Juniper
- **Affected products:** 5

## What is CVE-2023-44189? In plain terms

An attacker has to be on the same local network without logging in, and nobody has to click anything. If it works, the attacker can change some data and slow it down.

### The official description

An Origin Validation vulnerability in MAC address validation of Juniper Networks Junos OS Evolved on PTX10003 Series allows a network-adjacent attacker to bypass MAC address checking, allowing MAC addresses not intended to reach the adjacent LAN to be forwarded to the downstream network. Due to this issue, the router will start forwarding traffic if a valid route is present in forwarding-table, causing a loop and congestion in the downstream layer-2 domain connected to the device.

This issue affects Juniper Networks Junos OS Evolved on PTX10003 Series:

  *  All versions prior to 21.4R3-S4-EVO;
  *  22.1 versions prior to 22.1R3-S3-EVO;
  *  22.2 version 22.2R1-EVO and later versions;
  *  22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO;
  *  22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO;
  *  23.2 versions prior to 23.2R2-EVO.

### What kind of flaw is it?

- CWE-346: Origin Validation Error

### How an attack on it works

- Where an attacker can be: On the same local network
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can change some data and slow it down

Severity vector: `CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L`

## Is CVE-2023-44189 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.2%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 0.2%, 0.2%, 0.2%, 0.2%, 0.2%, 0.2%, 0.2%.

### Timeline

- 11 October 2023: Published
- 19 October 2023: Record last updated

### How Precursor Intelligence ranks it

CVE-2023-44189 scores **19 out of 100 (Info)**, with the action "Track".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2023-44189?

The published record lists 5 products. Versions are as published: "before 21.4" means every version up to, but not including, 21.4.

- [Junos OS Evolved](https://www.precursorintelligence.com/product/juniper/junos_os_evolved) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Operating system): before 21.4, 21.4, 21.4-r1, 21.4-r1-s1, 21.4-r1-s2, 21.4-r2, 21.4-r2-s1, 21.4-r2-s2, 21.4-r3, 21.4-r3-s1, 21.4-r3-s2, 21.4-r3-s3, 22.1-r1, 22.1-r1-s1, 22.1-r1-s2, 22.1-r2, 22.1-r2-s1, 22.1-r3, 22.1-r3-s1, 22.1-r3-s2, 22.2-r1, 22.2-r1-s1, 22.2-r2, 22.2-r2-s1, 22.2-r2-s2, 22.2-r3, 22.2-r3-s1, 22.3-r1, 22.3-r1-s1, 22.3-r1-s2, 22.3-r2, 22.3-r2-s1, 22.4-r1, 22.4-r1-s1, 22.4-r1-s2, 22.4-r2, 23.2-r1, 23.2-r1-s1
- [Ptx10003](https://www.precursorintelligence.com/product/juniper/ptx10003) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Ptx10003 160c](https://www.precursorintelligence.com/product/juniper/ptx10003_160c) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Ptx10003 80c](https://www.precursorintelligence.com/product/juniper/ptx10003_80c) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Ptx10003 81cd](https://www.precursorintelligence.com/product/juniper/ptx10003_81cd) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified

## How do I fix CVE-2023-44189?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [supportportal.juniper.net](https://supportportal.juniper.net/JSA73153) (Vendor advisory)

## Questions

### What is CVE-2023-44189?

CVE-2023-44189 is a medium-severity flaw in Junos OS Evolved from Juniper, published on 11 October 2023. An attacker has to be on the same local network without logging in, and nobody has to click anything. If it works, the attacker can change some data and slow it down.

### How serious is CVE-2023-44189?

It scores 5.4 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2023-44189 is 19 out of 100, which is Info. Its action is "Track". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2023-44189 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.2%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2023-44189 affect?

For Junos OS Evolved from Juniper: before 21.4, 21.4, 21.4-r1, 21.4-r1-s1, 21.4-r1-s2, 21.4-r2 and 32 more. The record lists 5 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2023-44189?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2023-44189 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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