CVE-2023-6906Public exploitNetwork attack vector

Unauthenticated code execution via oversized login body

Published Dec 18, 2023 · Updated May 7, 2025

Buffer overflow in TOTOLINK A7100RU 7.4cu.2313_B20191024 allows remote attackers to execute arbitrary commands through the login handler. In /cgi-bin/cstecgi.cgi?action=login, main() uses sprintf to construct a buffer from the POST body when flag=ie8 without checking its length. An unauthenticated network request is sufficient; the published proof of concept redirects control to system and launches a shell.

CVSS severity9.8
Critical
EPSS probability1.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in TOTOLINK A7100RU 7.4cu.2313_B20191024 allows remote attackers to execute arbitrary commands through the login handler. In /cgi-bin/cstecgi.cgi?action=login, main() uses sprintf to construct a buffer from the POST body when flag=ie8 without checking its length. An unauthenticated network request is sufficient; the published proof of concept redirects control to system and launches a shell.

The record

CVE
CVE-2023-6906
Published
Dec 18, 2023
Updated
May 7, 2025
Vendor
TOTOLINK
Product
A7100RU
Classifications
CWE-120, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 18, 2023CVE publishedPublication date reported by the CVE source.
  2. May 7, 2025Record 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=7.4cu.2313_B20191024

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TOTOLINK · A7100RUversion=7.4cu.2313_B20191024

Published CVSS scores

9.8VulDBCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1190Exploit Public-Facing Application

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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