# What is CVE-2020-29557?

> CVE-2020-29557 is a critical-severity flaw (CVSS 9.8) in Dir-825 R1 Firmware from Dlink, published on 29 January 2021. It is on the list of flaws known to be exploited, so criminals are already using it. The latest forecast puts its chance of use in the next 30 days at 54%. If you run an affected version, patch it first.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-29557

## At a glance

- **Verdict:** Fix this now. Attackers are using this flaw today. If you run an affected version, it goes to the top of your list.
- **Precursor Intelligence risk score:** 88 out of 100 (Critical); action: Emergency patch. Kept up to date as the evidence changes.
- **Severity:** Critical (CVSS 9.8 out of 10)
- **Known to be exploited:** Yes, it is on the government list of flaws known to be exploited
- **Chance of use in the next 30 days:** 54% (latest exploit-likelihood forecast)
- **Published:** 29 January 2021
- **Record last updated:** 22 October 2025
- **Main product:** Dir-825 R1 Firmware from Dlink
- **Affected products:** 1

## What is CVE-2020-29557? 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, change data and take it offline.

### The official description

An issue was discovered on D-Link DIR-825 R1 devices through 3.0.1 before 2020-11-20. A buffer overflow in the web interface allows attackers to achieve pre-authentication remote code execution.

### What kind of flaw is it?

- CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

### 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, change data and take it offline

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

## Is CVE-2020-29557 being exploited? Yes

Attackers are already using it. It is on the government list of flaws known to be exploited, and the latest forecast puts the chance of it being used in the next 30 days at 54%.

Exploit likelihood over the last 7 days: 54%, 54%, 54%, 54%, 54%, 54%, 54%.

### Timeline

- 29 January 2021: Published
- 22 October 2025: Record last updated
- 16 June 2026: Exploit likelihood fell

### How Precursor Intelligence ranks it

CVE-2020-29557 scores **88 out of 100 (Critical)**, with the action "Emergency patch".

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-2020-29557?

The published record lists 1 product.

- [Dir-825 R1 Firmware](https://www.precursorintelligence.com/product/dlink/dir-825_r1_firmware) by [Dlink](https://www.precursorintelligence.com/vendors/dlink) (Operating system): up to 3.0.1

## How do I fix CVE-2020-29557?

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 latest update from the vendor. The references list where the vendor has published details.
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. **Check it wasn’t used before you patched.** Because criminals are already using this flaw, look for signs of a break-in on affected systems using the vendor’s guidance.

### References

- [shaqed.github.io](https://shaqed.github.io/dlink/) (Broken link, Exploit, Third-party advisory)
- [dlink.ru](https://www.dlink.ru/ru/download2/5/19/2354/441/) (Product)
- [cisa.gov](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29557)

## Questions

### What is CVE-2020-29557?

CVE-2020-29557 is a critical-severity flaw in Dir-825 R1 Firmware from Dlink, published on 29 January 2021. 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, change data and take it offline.

### How serious is CVE-2020-29557?

It scores 9.8 out of 10 on the CVSS severity scale, which is critical. Our risk score for CVE-2020-29557 is 88 out of 100, which is Critical. Its action is "Emergency patch". Attackers are using this flaw today. If you run an affected version, it goes to the top of your list.

### Is CVE-2020-29557 being exploited?

Attackers are already using it. It is on the government list of flaws known to be exploited, and the latest forecast puts the chance of it being used in the next 30 days at 54%.

### Which versions does CVE-2020-29557 affect?

For Dir-825 R1 Firmware from Dlink: up to 3.0.1.

### How do I fix CVE-2020-29557?

Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. Because criminals are already using it, also check affected systems for signs of a break-in.

## Does CVE-2020-29557 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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