CVE-2026-51695Network attack vector

Unauthenticated DDNS changes via missing CGI authorization

Published Aug 31, 2026 · Updated Sep 1, 2026

Incorrect access control in TOTOLINK T6 4.1.5cu.748_B20211015 allows remote attackers to alter dynamic DNS configuration. The setDdnsCfg handler at /cgi-bin/cstecgi.cgi accepts a crafted POST request with topicurl=setDdnsCfg and applies attacker-supplied DDNS parameters without authentication. Network access to the management endpoint is sufficient, and exploitation changes router DDNS state rather than disclosing data or interrupting service.

CVSS severityUnavailable
Unscored
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect access control in TOTOLINK T6 4.1.5cu.748_B20211015 allows remote attackers to alter dynamic DNS configuration. The setDdnsCfg handler at /cgi-bin/cstecgi.cgi accepts a crafted POST request with topicurl=setDdnsCfg and applies attacker-supplied DDNS parameters without authentication. Network access to the management endpoint is sufficient, and exploitation changes router DDNS state rather than disclosing data or interrupting service.

The record

CVE
CVE-2026-51695
Published
Aug 31, 2026
Updated
Sep 1, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 2026Record 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

No CVSS assessment is available in this record.

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 exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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