CVE-2021-20157Public exploitNetwork attack vector

Unauthenticated reboot via hidden administrative command

Published Dec 30, 2021 · Updated Aug 3, 2024

Denial of service in TRENDnet TEW-827DRU firmware 2.08B01 allows remote attackers to reboot the router via its web interface. The unauthenticated apply_sec.cgi handler accepts action=tools_admin_elecom with command=restart and invokes the hidden administrative reboot path. Network access to the management interface is sufficient, and exploitation interrupts service by restarting the appliance.

CVSS severity7.5
High
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in TRENDnet TEW-827DRU firmware 2.08B01 allows remote attackers to reboot the router via its web interface. The unauthenticated apply_sec.cgi handler accepts action=tools_admin_elecom with command=restart and invokes the hidden administrative reboot path. Network access to the management interface is sufficient, and exploitation interrupts service by restarting the appliance.

The record

CVE
CVE-2021-20157
Published
Dec 30, 2021
Updated
Aug 3, 2024
Vendor
TRENDnet
Product
TEW-827DRU Firmware
Classifications
T1529
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 30, 2021CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.08B01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TRENDnet · TEW-827DRU Firmwareversion=2.08B01

Published CVSS scores

7.8NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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

T1529System Shutdown/Reboot

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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