What is CVE-2023-43239?

CVE-2023-43239 is a critical-severity vulnerability in Dlink Dir-816 A2, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2023-09-21.

How severe is CVE-2023-43239?

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

Buffer overflow in Dlink Dir-816 A2

CVE-2023-43239

D-Link DIR-816 A2 v1.10CNB05 was discovered to contain a stack overflow via parameter flag_5G in showMACfilterMAC.

Vulnerability class: Buffer Overflow

Published 2023-09-21 · 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: 0.144 (96.5th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.122 · newest: 0.144 · change: +0.021

Affected products

Dlink Dir-816 A2
Dlink Dir-816 A2 Firmware — versions 1.10cnb05

Weakness classification (CWE)

References

www.dlink.com/en/security-bulletin/ (Vendor Advisory)
github.com/peris-navince/founded-0-days/blob/main/Dlink/816/showMACfilterMAC/1… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2023-43239?: CVE-2023-43239 is a critical-severity vulnerability in Dlink Dir-816 A2, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2023-09-21.
How severe is CVE-2023-43239?: Critical severity. CVSS v3 base score is 9.8 out of 10.