How severe is CVE-2021-43722?

CVE-2021-43722 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-2021-43722 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43722?

CVE-2021-43722 affects Dlink Dir-645 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43722?

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-2021-43722 published?

CVE-2021-43722 was published on 2022-03-31 and last updated on 2026-06-17.

CVE-2021-43722

CVE-2021-43722 is a critical-severity vulnerability in Dlink Dir-645 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. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Dlink Dir-645 Firmware
Published: 2022-03-31
Last modified: 2026-06-17

Description

D-Link DIR-645 1.03 A1 is vulnerable to Buffer Overflow. The hnap_main function in the cgibin handler uses sprintf to format the soapaction header onto the stack and has no limit on the size.

Frequently asked questions

What is CVE-2021-43722?: D-Link DIR-645 1.03 A1 is vulnerable to Buffer Overflow. The hnap_main function in the cgibin handler uses sprintf to format the soapaction header onto the stack and has no limit on the size.
How severe is CVE-2021-43722?: CVE-2021-43722 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-2021-43722 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43722?: CVE-2021-43722 affects Dlink Dir-645 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43722?: 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-2021-43722 published?: CVE-2021-43722 was published on 2022-03-31 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:dlink:dir-645_firmware:1.03:*:*:*:*:*:*:*

More vulnerabilities in Dlink Dir-645 Firmware

CVE-2015-2052 — Critical (CVSS 10.0): Stack-based buffer overflow in the DIR-645 Wired/Wireless Router Rev. Ax with firmware 1.04b12 and earlier allows…
CVE-2018-25115 — Critical (CVSS 9.8): Multiple D-Link DIR-series routers, including DIR-110, DIR-412, DIR-600, DIR-610, DIR-615, DIR-645, and DIR-815…
CVE-2023-36089 — Critical (CVSS 9.8): Authentication Bypass vulnerability in D-Link DIR-645 firmware version 1.03 allows remote attackers to gain escalated…
CVE-2022-46475 — Critical (CVSS 9.8): D-Link DIR 645A1 1.06B01_Beta01 was discovered to contain a stack overflow via the service= variable in the…
CVE-2022-32092 — Critical (CVSS 9.8): D-Link DIR-645 v1.03 was discovered to contain a command injection vulnerability via the QUERY_STRING parameter at…
CVE-2013-7471 — Critical (CVSS 9.8): An issue was discovered in soap.cgi?service=WANIPConn1 on D-Link DIR-845 before v1.02b03, DIR-600 before v2.17b01,…

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