How severe is CVE-2021-21913?

CVE-2021-21913 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-2021-21913 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21913?

CVE-2021-21913 affects Dlink Dir-3040 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21913?

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-2021-21913 published?

CVE-2021-21913 was published on 2021-09-23 and last updated on 2026-06-17.

CVE-2021-21913

CVE-2021-21913 is a critical-severity vulnerability in Dlink Dir-3040 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-798.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-798
Affected product: Dlink Dir-3040 Firmware
Published: 2021-09-23
Last modified: 2026-06-17

Description

An information disclosure vulnerability exists in the WiFi Smart Mesh functionality of D-LINK DIR-3040 1.13B03. A specially-crafted network request can lead to command execution. An attacker can connect to the MQTT service to trigger this vulnerability.

Frequently asked questions

What is CVE-2021-21913?: An information disclosure vulnerability exists in the WiFi Smart Mesh functionality of D-LINK DIR-3040 1.13B03. A specially-crafted network request can lead to command execution. An attacker can connect to the MQTT service to trigger this vulnerability.
How severe is CVE-2021-21913?: CVE-2021-21913 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-2021-21913 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21913?: CVE-2021-21913 affects Dlink Dir-3040 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21913?: 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-2021-21913 published?: CVE-2021-21913 was published on 2021-09-23 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1361

Affected products (1)

cpe:2.3:o:dlink:dir-3040_firmware:1.13b03:*:*:*:*:*:*:*

More vulnerabilities in Dlink Dir-3040 Firmware

CVE-2022-44832 — Critical (CVSS 9.8): D-Link DIR-3040 device with firmware 120B03 was discovered to contain a command injection vulnerability via the…
CVE-2021-21820 — Critical (CVSS 9.8): A hard-coded password vulnerability exists in the Libcli Test Environment functionality of D-LINK DIR-3040 1.13B03. A…
CVE-2023-41230 — High (CVSS 8.8): D-Link DIR-3040 HTTP Request Processing Referer Stack-Based Buffer Overflow Remote Code Execution Vulnerability. This…
CVE-2023-41229 — High (CVSS 8.8): D-Link DIR-3040 HTTP Request Processing Referer Heap-Based Buffer Overflow Remote Code Execution Vulnerability. This…
CVE-2022-43648 — High (CVSS 8.8): This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link…
CVE-2022-1262 — High (CVSS 7.8): A command injection vulnerability in the protest binary allows an attacker with access to the remote command line…

All CVEs affecting Dlink Dir-3040 Firmware →

Other CWE-798 (Use of Hard-coded Credentials) vulnerabilities

CVE-2026-13768 — Critical (CVSS 10.0): Gardyn devices expose a privileged iothubowner key. Access to this key will allow a malicious user to invoke an IoTHub…
CVE-2026-45631 — Critical (CVSS 10.0): Dokploy is a free, self-hostable Platform as a Service (PaaS). From 0.27.0 to before 0.29.3, a hardcoded…
CVE-2026-22769 — Critical (CVSS 10.0): Dell RecoverPoint for Virtual Machines, versions prior to 6.0.3.1 HF1, contain a hardcoded credential vulnerability.…
CVE-2025-42890 — Critical (CVSS 10.0): SQL Anywhere Monitor (Non-GUI) baked credentials into the code,exposing the resources or functionality to unintended…
CVE-2025-7503 — Critical (CVSS 10.0): An OEM IP camera manufactured by Shenzhen Liandian Communication Technology LTD exposes a Telnet service (port 23) with…
CVE-2025-20309 — Critical (CVSS 10.0): A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session…

Browse all CWE-798 (Use of Hard-coded Credentials) vulnerabilities →