How severe is CVE-2025-5621?

CVE-2025-5621 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2025-5621 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-5621?

CVE-2025-5621 affects Dlink Dir-816 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-5621?

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

Does CVE-2025-5621 have an EU (EUVD) identifier?

Yes. CVE-2025-5621 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16942.

When was CVE-2025-5621 published?

CVE-2025-5621 was published on 2025-06-05 and last updated on 2026-06-17.

CVE-2025-5621

CVE-2025-5621 is a high-severity vulnerability in Dlink Dir-816 Firmware with a CVSS 3.x base score of 7.3. 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-78.

Key facts

Severity: High (CVSS 3.x base score 7.3)
CVSS v2: 7.5
CVSS v4: 6.9
EPSS exploit prediction: 7% (93rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-16942
Weakness: CWE-78
Affected product: Dlink Dir-816 Firmware
Published: 2025-06-05
Last modified: 2026-06-17

Description

A vulnerability has been found in D-Link DIR-816 1.10CNB05 and classified as critical. Affected by this vulnerability is the function qosClassifier of the file /goform/qosClassifier. The manipulation of the argument dip_address/sip_address leads to os command injection. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.

Frequently asked questions

What is CVE-2025-5621?: A vulnerability has been found in D-Link DIR-816 1.10CNB05 and classified as critical. Affected by this vulnerability is the function qosClassifier of the file /goform/qosClassifier. The manipulation of the argument dip_address/sip_address leads to os command injection. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.
How severe is CVE-2025-5621?: CVE-2025-5621 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2025-5621 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-5621?: CVE-2025-5621 affects Dlink Dir-816 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-5621?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-5621 have an EU (EUVD) identifier?: Yes. CVE-2025-5621 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16942.
When was CVE-2025-5621 published?: CVE-2025-5621 was published on 2025-06-05 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:dlink:dir-816_firmware:1.10cnb05:*:*:*:*:*:*:*

More vulnerabilities in Dlink Dir-816 Firmware

CVE-2026-4184 — Critical (CVSS 9.8): A vulnerability was detected in D-Link DIR-816 1.10CNB05. Affected by this vulnerability is an unknown functionality of…
CVE-2026-4183 — Critical (CVSS 9.8): A security vulnerability has been detected in D-Link DIR-816 1.10CNB05. Affected is an unknown function of the file…
CVE-2026-4182 — Critical (CVSS 9.8): A weakness has been identified in D-Link DIR-816 1.10CNB05. This impacts an unknown function of the file…
CVE-2026-4181 — Critical (CVSS 9.8): A security flaw has been discovered in D-Link DIR-816 1.10CNB05. This affects an unknown function of the file…
CVE-2025-45931 — Critical (CVSS 9.8): An issue D-Link DIR-816-A2 DIR-816A2_FWv1.10CNB05_R1B011D88210 allows a remote attacker to execute arbitrary code via…
CVE-2025-5630 — Critical (CVSS 9.8): A vulnerability has been found in D-Link DIR-816 1.10CNB05 and classified as critical. This vulnerability affects…

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