# What is CVE-2021-42016?

> CVE-2021-42016 is a high-severity flaw (CVSS 7.5) in Ruggedcom Ros from Siemens, published on 8 March 2022. 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 0.6%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-42016

## 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:** 46 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 7.5 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:** 0.6% (latest exploit-likelihood forecast)
- **Published:** 8 March 2022
- **Record last updated:** 12 August 2025
- **Main product:** Ruggedcom Ros from Siemens
- **Affected products:** 1

## What is CVE-2021-42016? 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 read data.

### The official description

A vulnerability has been identified in RUGGEDCOM i800, RUGGEDCOM i801, RUGGEDCOM i802, RUGGEDCOM i803, RUGGEDCOM M2100, RUGGEDCOM M2100F, RUGGEDCOM M2200, RUGGEDCOM M2200F, RUGGEDCOM M969, RUGGEDCOM M969F, RUGGEDCOM RMC30, RUGGEDCOM RMC8388 V4.X, RUGGEDCOM RMC8388 V5.X, RUGGEDCOM RP110, RUGGEDCOM RS1600, RUGGEDCOM RS1600F, RUGGEDCOM RS1600T, RUGGEDCOM RS400, RUGGEDCOM RS400F, RUGGEDCOM RS401, RUGGEDCOM RS416, RUGGEDCOM RS416F, RUGGEDCOM RS416P, RUGGEDCOM RS416PF, RUGGEDCOM RS416Pv2 V4.X, RUGGEDCOM RS416Pv2 V5.X, RUGGEDCOM RS416v2 V4.X, RUGGEDCOM RS416v2 V5.X, RUGGEDCOM RS8000, RUGGEDCOM RS8000A, RUGGEDCOM RS8000H, RUGGEDCOM RS8000T, RUGGEDCOM RS900, RUGGEDCOM RS900 (32M) V4.X, RUGGEDCOM RS900 (32M) V5.X, RUGGEDCOM RS900F, RUGGEDCOM RS900G, RUGGEDCOM RS900G (32M) V4.X, RUGGEDCOM RS900G (32M) V5.X, RUGGEDCOM RS900GF, RUGGEDCOM RS900GP, RUGGEDCOM RS900GPF, RUGGEDCOM RS900L, RUGGEDCOM RS900M-GETS-C01, RUGGEDCOM RS900M-GETS-XX, RUGGEDCOM RS900M-STND-C01, RUGGEDCOM RS900M-STND-XX, RUGGEDCOM RS900W, RUGGEDCOM RS910, RUGGEDCOM RS910L, RUGGEDCOM RS910W, RUGGEDCOM RS920L, RUGGEDCOM RS920W, RUGGEDCOM RS930L, RUGGEDCOM RS930W, RUGGEDCOM RS940G, RUGGEDCOM RS940GF, RUGGEDCOM RS969, RUGGEDCOM RSG2100, RUGGEDCOM RSG2100 (32M) V4.X, RUGGEDCOM RSG2100 (32M) V5.X, RUGGEDCOM RSG2100F, RUGGEDCOM RSG2100P, RUGGEDCOM RSG2100P (32M) V4.X, RUGGEDCOM RSG2100P (32M) V5.X, RUGGEDCOM RSG2100PF, RUGGEDCOM RSG2200, RUGGEDCOM RSG2200F, RUGGEDCOM RSG2288 V4.X, RUGGEDCOM RSG2288 V5.X, RUGGEDCOM RSG2300 V4.X, RUGGEDCOM RSG2300 V5.X, RUGGEDCOM RSG2300F, RUGGEDCOM RSG2300P V4.X, RUGGEDCOM RSG2300P V5.X, RUGGEDCOM RSG2300PF, RUGGEDCOM RSG2488 V4.X, RUGGEDCOM RSG2488 V5.X, RUGGEDCOM RSG2488F, RUGGEDCOM RSG907R, RUGGEDCOM RSG908C, RUGGEDCOM RSG909R, RUGGEDCOM RSG910C, RUGGEDCOM RSG920P V4.X, RUGGEDCOM RSG920P V5.X, RUGGEDCOM RSL910, RUGGEDCOM RST2228, RUGGEDCOM RST2228P, RUGGEDCOM RST916C, RUGGEDCOM RST916P. A timing attack, in a third-party component, could make the retrieval of the private key possible, used for encryption of sensitive data.

If a threat actor were to exploit this, the data integrity and security could be compromised.

### What kind of flaw is it?

- CWE-203: Observable Discrepancy
- CWE-208: Observable Timing Discrepancy

### 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 read data

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

## Is CVE-2021-42016 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 0.6%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 0.6%, 0.6%, 0.6%, 0.6%, 0.6%, 0.6%, 0.6%.

### Timeline

- 8 March 2022: Published
- 12 August 2025: Record last updated

### How Precursor Intelligence ranks it

CVE-2021-42016 scores **46 out of 100 (Medium)**, with the action "Plan remediation".

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-2021-42016?

The published record lists 1 product. Versions are as published: "before 5.6.0" means every version up to, but not including, 5.6.0.

- [Ruggedcom Ros](https://www.precursorintelligence.com/product/siemens/ruggedcom_ros) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): all versions, before 5.6.0

## How do I fix CVE-2021-42016?

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

- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-256353.pdf) (Patch, Vendor advisory)
- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/html/ssa-256353.html)

## Questions

### What is CVE-2021-42016?

CVE-2021-42016 is a high-severity flaw in Ruggedcom Ros from Siemens, published on 8 March 2022. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data.

### How serious is CVE-2021-42016?

It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2021-42016 is 46 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2021-42016 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 0.6%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2021-42016 affect?

For Ruggedcom Ros from Siemens: all versions, before 5.6.0.

### How do I fix CVE-2021-42016?

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-2021-42016 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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