How severe is CVE-2021-45740?

CVE-2021-45740 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-45740 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-45740?

CVE-2021-45740 affects Totolink A720r Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-45740?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-45740 published?

CVE-2021-45740 was published on 2022-02-04 and last updated on 2026-06-17.

CVE-2021-45740

CVE-2021-45740 is a critical-severity vulnerability in Totolink A720r Firmware with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Totolink A720r Firmware
Published: 2022-02-04
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-45740?: CVE-2021-45740 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-45740 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-45740?: CVE-2021-45740 affects Totolink A720r Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-45740?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-45740 published?: CVE-2021-45740 was published on 2022-02-04 and last updated on 2026-06-17.

References

https://github.com/pjqwudi/my_vuln/blob/main/totolink/vuln_4/4.md

Affected products (1)

cpe:2.3:o:totolink:a720r_firmware:4.1.5cu.470_b20200911:*:*:*:*:*:*:*

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