How severe is CVE-2021-31326?

CVE-2021-31326 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-2021-31326 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-2021-31326?

CVE-2021-31326 affects Dlink Dir-816 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-31326?

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-2021-31326 published?

CVE-2021-31326 was published on 2022-03-24 and last updated on 2026-06-17.

CVE-2021-31326

CVE-2021-31326 is a critical-severity vulnerability in Dlink Dir-816 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 9.0
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Dlink Dir-816 Firmware
Published: 2022-03-24
Last modified: 2026-06-17

Description

D-Link DIR-816 A2 1.10 B05 allows unauthenticated attackers to arbitrarily reset the device via a crafted tokenid parameter to /goform/form2Reboot.cgi.

Frequently asked questions

What is CVE-2021-31326?: D-Link DIR-816 A2 1.10 B05 allows unauthenticated attackers to arbitrarily reset the device via a crafted tokenid parameter to /goform/form2Reboot.cgi.
How severe is CVE-2021-31326?: CVE-2021-31326 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-2021-31326 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-2021-31326?: CVE-2021-31326 affects Dlink Dir-816 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-31326?: 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-2021-31326 published?: CVE-2021-31326 was published on 2022-03-24 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…

All CVEs affecting Dlink Dir-816 Firmware →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →