# What is CVE-2021-35237?

> CVE-2021-35237 is a medium-severity flaw (CVSS 4.3) in Kiwi Syslog Server from Solarwinds, published on 29 October 2021. 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 1.0%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.edgeprotect.io/what-is/cve-2021-35237

## At a glance

- **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle.
- **EdgeProtect risk score:** 19 out of 100 (Info); action: Track. Kept up to date as the evidence changes.
- **Severity:** Medium (CVSS 4.3 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:** 1.0% (latest exploit-likelihood forecast)
- **Published:** 29 October 2021
- **Record last updated:** 16 September 2024
- **Main product:** Kiwi Syslog Server from Solarwinds
- **Affected products:** 1

## What is CVE-2021-35237? In plain terms

It can be attacked from anywhere on the internet without logging in, but a person has to take an action first. If it works, the attacker can change some data.

### The official description

A missing HTTP header (X-Frame-Options) in Kiwi Syslog Server has left customers vulnerable to click jacking. Clickjacking is an attack that occurs when an attacker uses a transparent iframe in a window to trick a user into clicking on an actionable item, such as a button or link, to another server in which they have an identical webpage. The attacker essentially hijacks the user activity intended for the original server and sends them to the other server. This is an attack on both the user and the server.

### What kind of flaw is it?

- CWE-1021: Improper Restriction of Rendered UI Layers or Frames

### 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: Yes, a person has to take an action
- What an attacker gets: Can change some data

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

## Is CVE-2021-35237 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 1.0%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 1.0%, 1.0%, 1.0%, 1.0%, 1.0%, 1.0%, 1.0%.

### Timeline

- 29 October 2021: Published
- 16 September 2024: Record last updated

### How EdgeProtect ranks it

CVE-2021-35237 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: key context
- Real threat activity around it: key context

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-2021-35237?

The published record lists 1 product.

- [Kiwi Syslog Server](https://www.edgeprotect.io/product/solarwinds/kiwi_syslog_server) by [Solarwinds](https://www.edgeprotect.io/vendors/solarwinds) (Application): up to 9.7.2

## How do I fix CVE-2021-35237?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? EdgeProtect 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 advisories and patch notes 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

- [documentation.solarwinds.com](https://documentation.solarwinds.com/en/success_center/kss/content/release_notes/kss_9-8_release_notes.htm) (Release notes, Vendor advisory)
- [solarwinds.com](https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35237) (Vendor advisory)

## Questions

### What is CVE-2021-35237?

CVE-2021-35237 is a medium-severity flaw in Kiwi Syslog Server from Solarwinds, published on 29 October 2021. It can be attacked from anywhere on the internet without logging in, but a person has to take an action first. If it works, the attacker can change some data.

### How serious is CVE-2021-35237?

It scores 4.3 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2021-35237 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-2021-35237 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 1.0%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2021-35237 affect?

For Kiwi Syslog Server from Solarwinds: up to 9.7.2.

### How do I fix CVE-2021-35237?

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-2021-35237 affect you?

EdgeProtect 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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