How severe is CVE-2021-43662?

CVE-2021-43662 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-43662 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43662?

CVE-2021-43662 primarily affects Totolink Ex300 V2 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43662?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43662 published?

CVE-2021-43662 was published on 2022-03-31 and last updated on 2026-06-17.

CVE-2021-43662

CVE-2021-43662 is a medium-severity vulnerability in Totolink Ex300 V2 Firmware with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 3.3
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Totolink Ex300 V2 Firmware
Published: 2022-03-31
Last modified: 2026-06-17

Description

totolink EX300_v2, ver V4.0.3c.140_B20210429 and A720R ,ver V4.1.5cu.470_B20200911 have an issue which causes uncontrolled resource consumption.

Frequently asked questions

What is CVE-2021-43662?: totolink EX300_v2, ver V4.0.3c.140_B20210429 and A720R ,ver V4.1.5cu.470_B20200911 have an issue which causes uncontrolled resource consumption.
How severe is CVE-2021-43662?: CVE-2021-43662 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-43662 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43662?: CVE-2021-43662 primarily affects Totolink Ex300 V2 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43662?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43662 published?: CVE-2021-43662 was published on 2022-03-31 and last updated on 2026-06-17.

References

https://github.com/chibataiki/iot-vuls/blob/main/totolink/dos.md

Affected products (2)

cpe:2.3:o:totolink:ex300_v2_firmware:4.0.3c.140_b20210429:*:*:*:*:*:*:*
cpe:2.3:o:totolink:a720r_firmware:4.1.5cu.470_b20200911:*:*:*:*:*:*:*

More vulnerabilities in Totolink Ex300 V2 Firmware

CVE-2022-32449 — Critical (CVSS 9.8): TOTOLINK EX300_V2 V4.0.3c.7484 was discovered to contain a command injection vulnerability via the langType parameter…
CVE-2022-25008 — High (CVSS 8.8): totolink EX300_v2 V4.0.3c.140_B20210429 and EX1200T V4.1.2cu.5230_B20210706 does not contain an authentication…
CVE-2021-43664 — High (CVSS 8.1): totolink EX300_v2 V4.0.3c.140_B20210429 was discovered to contain a command injection vulnerability via the component…
CVE-2021-43663 — High (CVSS 7.5): totolink EX300_v2 V4.0.3c.140_B20210429 was discovered to contain a command injection vulnerability via the component…
CVE-2021-43661 — Medium (CVSS 6.1): totolink EX300_v2 V4.0.3c.140_B20210429 was discovered to contain a reflected cross-site scripting (XSS) vulnerability…

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