# What is CVE-2023-28961?

> CVE-2023-28961 is a medium-severity flaw (CVSS 5.3) in Junos from Juniper, published on 17 April 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 0.4%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2023-28961

## 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:** 22 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes.
- **Severity:** Medium (CVSS 5.3 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:** 0.4% (latest exploit-likelihood forecast)
- **Published:** 17 April 2023
- **Record last updated:** 28 April 2023
- **Main product:** Junos from Juniper
- **Affected products:** 20

## What is CVE-2023-28961? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change some data.

### The official description

An Improper Handling of Unexpected Data Type vulnerability in IPv6 firewall filter processing of Juniper Networks Junos OS on the ACX Series devices will prevent a firewall filter with the term 'from next-header ah' from being properly installed in the packet forwarding engine (PFE). There is no immediate indication of an incomplete firewall filter commit shown at the CLI, which could allow an attacker to send valid packets to or through the device that were explicitly intended to be dropped. An indication that the filter was not installed can be identified with the following logs: fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_rule_prepare : Config failed: Unsupported Ip-protocol 51 in the filter lo0.0-inet6-i fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_rule_prepare : Please detach the filter, remove unsupported match and re-attach fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_process_rule : Status:104 dnx_dfw_rule_prepare failed fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_process_filter : Status:104 dnx_dfw_process_rule failed fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_update_filter_in_hw : Status:104 Could not process filter(lo0.0-inet6-i) for rule expansion Unsupported match, action present. fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_create_hw_instance : Status:104 Could not program dfw(lo0.0-inet6-i) type(IFP_DFLT_INET6_Lo0_FILTER)! [104] fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_bind_shim : [104] Could not create dfw(lo0.0-inet6-i) type(IFP_DFLT_INET6_Lo0_FILTER) fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_update_resolve : [100] Failed to bind filter(3) to bind point fpc0 ACX_DFW_CFG_FAILED: ACX Error (dfw):dnx_dfw_change_end : dnx_dfw_update_resolve (resolve type) failed This issue affects Juniper Networks Junos OS on ACX Series: All versions prior to 20.2R3-S7; 20.4 versions prior to 20.4R3-S4; 21.1 versions prior to 21.1R3-S3; 21.2 versions prior to 21.2R3-S4; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R2.

### What kind of flaw is it?

- CWE-241: Improper Handling of Unexpected Data Type

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- 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

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

## Is CVE-2023-28961 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 0.4%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 0.4%, 0.4%, 0.4%, 0.4%, 0.4%, 0.4%, 0.4%.

### Timeline

- 17 April 2023: Published
- 28 April 2023: Record last updated

### How Precursor Intelligence ranks it

CVE-2023-28961 scores **22 out of 100 (Low)**, with the action "Monitor".

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-2023-28961?

The published record lists 20 products. Versions are as published: "before 20.2" means every version up to, but not including, 20.2.

- [Junos](https://www.precursorintelligence.com/product/juniper/junos) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Operating system): before 20.2, 20.2, 20.2-r1, 20.2-r1-s1, 20.2-r1-s2, 20.2-r1-s3, 20.2-r2, 20.2-r2-s1, 20.2-r2-s2, 20.2-r2-s3, 20.2-r3, 20.2-r3-s1, 20.2-r3-s2, 20.2-r3-s3, 20.2-r3-s4, 20.2-r3-s5, 20.2-r3-s6, 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2, 20.4-r3, 20.4-r3-s1, 20.4-r3-s2, 20.4-r3-s3, 21.1, 21.1-r1, 21.1-r1-s1, 21.1-r2, 21.1-r2-s1, 21.1-r2-s2, 21.1-r3, 21.1-r3-s1, 21.1-r3-s2, 21.2, 21.2-r1, 21.2-r1-s1, 21.2-r1-s2 and 24 more
- [Acx1000](https://www.precursorintelligence.com/product/juniper/acx1000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx1100](https://www.precursorintelligence.com/product/juniper/acx1100) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx2000](https://www.precursorintelligence.com/product/juniper/acx2000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx2100](https://www.precursorintelligence.com/product/juniper/acx2100) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx2200](https://www.precursorintelligence.com/product/juniper/acx2200) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx4000](https://www.precursorintelligence.com/product/juniper/acx4000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx500](https://www.precursorintelligence.com/product/juniper/acx500) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx5000](https://www.precursorintelligence.com/product/juniper/acx5000) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx5048](https://www.precursorintelligence.com/product/juniper/acx5048) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx5096](https://www.precursorintelligence.com/product/juniper/acx5096) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx5400](https://www.precursorintelligence.com/product/juniper/acx5400) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx5448](https://www.precursorintelligence.com/product/juniper/acx5448) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx5800](https://www.precursorintelligence.com/product/juniper/acx5800) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx6300](https://www.precursorintelligence.com/product/juniper/acx6300) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx6360](https://www.precursorintelligence.com/product/juniper/acx6360) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx710](https://www.precursorintelligence.com/product/juniper/acx710) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx7100-32c](https://www.precursorintelligence.com/product/juniper/acx7100-32c) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx7100-48l](https://www.precursorintelligence.com/product/juniper/acx7100-48l) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified
- [Acx7509](https://www.precursorintelligence.com/product/juniper/acx7509) by [Juniper](https://www.precursorintelligence.com/vendors/juniper) (Hardware): version not specified

## How do I fix CVE-2023-28961?

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/JSA70586) (Vendor advisory)

## Questions

### What is CVE-2023-28961?

CVE-2023-28961 is a medium-severity flaw in Junos from Juniper, published on 17 April 2023. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change some data.

### How serious is CVE-2023-28961?

It scores 5.3 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2023-28961 is 22 out of 100, which is Low. Its action is "Monitor". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2023-28961 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 0.4%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2023-28961 affect?

For Junos from Juniper: before 20.2, 20.2, 20.2-r1, 20.2-r1-s1, 20.2-r1-s2, 20.2-r1-s3 and 58 more. The record lists 20 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2023-28961?

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-2023-28961 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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