CVE-2021-20158Public exploitNetwork attack vector

Administrative takeover via unauthenticated password reset

Published Dec 30, 2021 · Updated Aug 3, 2024

Authentication bypass in TRENDnet TEW-827DRU firmware 2.08B01 allows remote attackers to reset the router administrator password. The /apply_sec.cgi handler accepts an unauthenticated tools_admin_elecom request and writes the supplied admin_password value. Network access to the web management interface is sufficient, and the password reset grants administrative control over the device.

CVSS severity9.8
Critical
EPSS probability10.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in TRENDnet TEW-827DRU firmware 2.08B01 allows remote attackers to reset the router administrator password. The /apply_sec.cgi handler accepts an unauthenticated tools_admin_elecom request and writes the supplied admin_password value. Network access to the web management interface is sufficient, and the password reset grants administrative control over the device.

The record

CVE
CVE-2021-20158
Published
Dec 30, 2021
Updated
Aug 3, 2024
Vendor
TRENDnet
Product
TEW-827DRU
Classifications
CWE-306, T1098
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-827DRUversion=2.08B01

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8TenableCVSS:3.0/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-306Missing Authentication for Critical Function
T1098Account Manipulation

Public exploit references

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Technologies

Your stack

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Your stack

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