CVE-2023-7221Network attack vector

Unauthenticated memory corruption via oversized v41 parameter

Published Jan 9, 2024 · Updated May 14, 2025

Buffer overflow in the T6 login handler in TOTOLINK T6 4.1.9cu.5241_B20210923 allows remote attackers to corrupt memory via HTTP POST. The main function in /cgi-bin/cstecgi.cgi?action=login copies an oversized v41 parameter into a fixed-size buffer without checking its length. No authentication or user interaction is required, and successful exploitation can compromise confidentiality, integrity, and availability.

CVSS severity9.8
Critical
EPSS probability1.52%
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 the T6 login handler in TOTOLINK T6 4.1.9cu.5241_B20210923 allows remote attackers to corrupt memory via HTTP POST. The main function in /cgi-bin/cstecgi.cgi?action=login copies an oversized v41 parameter into a fixed-size buffer without checking its length. No authentication or user interaction is required, and successful exploitation can compromise confidentiality, integrity, and availability.

The record

CVE
CVE-2023-7221
Published
Jan 9, 2024
Updated
May 14, 2025
Vendor
TOTOLINK
Product
T6
Classifications
CWE-120, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2024CVE publishedPublication date reported by the CVE source.
  2. May 14, 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=4.1.9cu.5241_B20210923

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TOTOLINK · T6version=4.1.9cu.5241_B20210923

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0VulDBAV:N/AC:L/Au:N/C:C/I:C/A:C

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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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