CVE-2021-31326Public exploitNetwork attack vector

Unauthenticated device reboot via unchecked token

Published Mar 23, 2022 · Updated Aug 3, 2024

Improper authentication in D-Link DIR-816 A2 firmware 1.10CNB05 allows remote attackers to reboot the router without credentials. The /goform/form2Reboot.cgi endpoint accepts an attacker-controlled tokenid value and reaches the reboot handler without validating an authenticated session. Reachability of the HTTP management interface is sufficient, and a successful request interrupts routing service by restarting the device.

CVSS severity9.8
Critical
EPSS probability2.20%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in D-Link DIR-816 A2 firmware 1.10CNB05 allows remote attackers to reboot the router without credentials. The /goform/form2Reboot.cgi endpoint accepts an attacker-controlled tokenid value and reaches the reboot handler without validating an authenticated session. Reachability of the HTTP management interface is sufficient, and a successful request interrupts routing service by restarting the device.

The record

CVE
CVE-2021-31326
Published
Mar 23, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.0NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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