CVE-2021-33266

Name: CVE-2021-33266
Creator: NVD / NIST
Published: 2021-12-01T22:15:07.647+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 16.87%

Last modified Jun 17, 2026

CVE-2021-33266 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. D-Link DIR-809 devices with firmware through DIR-809Ax_FW1.12WWB03_20190410 were discovered to contain a stack buffer overflow vulnerability in the function FUN_8004776c in /formVirtualApp. This vulnerability is triggered via a crafted POST request.. EPSS estimates a 16.87% chance of exploitation in the next 30 days.

Description

D-Link DIR-809 devices with firmware through DIR-809Ax_FW1.12WWB03_20190410 were discovered to contain a stack buffer overflow vulnerability in the function FUN_8004776c in /formVirtualApp. This vulnerability is triggered via a crafted POST request.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

16.87%

96.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Dlink	Dir-809 Firmware	<= 1.12wwb03

References

https://github.com/Lnkvct/IoT-poc/tree/master/D-Link-DIR809/vuln04Exploit, Third Party Advisory
https://www.dlink.com/en/security-bulletin/Vendor Advisory
https://github.com/Lnkvct/IoT-poc/tree/master/D-Link-DIR809/vuln04Exploit, Third Party Advisory
https://www.dlink.com/en/security-bulletin/Vendor Advisory

Timeline

Published: Dec 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33266?

How severe is CVE-2021-33266?

CVE-2021-33266 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 16.87% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33266?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33266?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST