What is CVE-2021-45740?

CVE-2021-45740 is a critical-severity vulnerability in Totolink A720r. CVSS score: 9.8/10. Published 2022-02-04.

How severe is CVE-2021-45740?

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

Is CVE-2021-45740 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Totolink A720r

CVE-2021-45740

TOTOLINK A720R v4.1.5cu.470_B20200911 was discovered to contain a stack overflow in the setWiFiWpsStart function. This vulnerability allows attackers to cause a Denial of Service (DoS) via the pin parameter.

Published 2022-02-04 · 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: 0.014 (70.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 70.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Totolink A720r
Totolink A720r Firmware — versions 4.1.5cu.470_b20200911

Public proof-of-concept exploits

References

github.com/pjqwudi/my_vuln/blob/main/totolink/vuln_4/4.md (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-45740?: CVE-2021-45740 is a critical-severity vulnerability in Totolink A720r. CVSS score: 9.8/10. Published 2022-02-04.
How severe is CVE-2021-45740?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-45740 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.