How severe is CVE-2021-21816?

CVE-2021-21816 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-21816 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 36% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21816?

CVE-2021-21816 affects Dlink Dir-3040 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21816?

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

When was CVE-2021-21816 published?

CVE-2021-21816 was published on 2021-07-16 and last updated on 2026-06-17.

CVE-2021-21816

CVE-2021-21816 is a medium-severity vulnerability in Dlink Dir-3040 Firmware with a CVSS 3.x base score of 4.3. Its EPSS exploit-prediction score of 36% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 36% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Dlink Dir-3040 Firmware
Published: 2021-07-16
Last modified: 2026-06-17

Description

An information disclosure vulnerability exists in the Syslog functionality of D-LINK DIR-3040 1.13B03. A specially crafted network request can lead to the disclosure of sensitive information. An attacker can send an HTTP request to trigger this vulnerability.

Frequently asked questions

What is CVE-2021-21816?: An information disclosure vulnerability exists in the Syslog functionality of D-LINK DIR-3040 1.13B03. A specially crafted network request can lead to the disclosure of sensitive information. An attacker can send an HTTP request to trigger this vulnerability.
How severe is CVE-2021-21816?: CVE-2021-21816 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-21816 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 36% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21816?: CVE-2021-21816 affects Dlink Dir-3040 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21816?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21816 published?: CVE-2021-21816 was published on 2021-07-16 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1281

Affected products (1)

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

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