What is CVE-2020-29557?

CVE-2020-29557 is a critical-severity vulnerability in Dlink Dir-825, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2021-01-29.

How severe is CVE-2020-29557?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2020-29557 known to be exploited?

Yes. CVE-2020-29557 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 2 public proof-of-concept repositories are indexed.

Buffer overflow in Dlink Dir-825

CVE-2020-29557

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.

Vulnerability class: Buffer Overflow

Published 2021-01-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.543 (99.0th percentile), scored 2026-10-18.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.543 · newest: 0.543 · change: 0.000

Affected products

Dlink Dir-825 — versions r1
Dlink Dir-825\/a — versions d1a
Dlink Dir-825\/ac — versions e, e1a
Dlink Dir-825\/acf — versions f1
Dlink Dir-825\/gf — versions gf
Dlink Dir-825 R1 Firmware

Weakness classification (CWE)

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

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

www.dlink.ru/ru/download2/5/19/2354/441/ (Product)
shaqed.github.io/dlink/ (Exploit, Third Party Advisory, Broken Link)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2020-29557?: CVE-2020-29557 is a critical-severity vulnerability in Dlink Dir-825, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2021-01-29.
How severe is CVE-2020-29557?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2020-29557 known to be exploited?: Yes. CVE-2020-29557 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 2 public proof-of-concept repositories are indexed.