CVE-2026-0625Known exploitationPublic exploitNetwork attack vector

Unauthenticated DNS hijacking via exposed configuration endpoint

Published Jan 5, 2026 · Updated Jan 5, 2026

Authentication bypass in D-Link DSL gateways with affected legacy firmware allows remote attackers to change DNS settings without credentials. The dnscfg.cgi endpoint accepts direct unauthenticated requests and writes supplied primary or secondary DNS server values into device configuration. Network reachability to the web interface is sufficient, and successful modification redirects client DNS queries to attacker-controlled infrastructure.

CVSS severity9.3
Critical
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in D-Link DSL gateways with affected legacy firmware allows remote attackers to change DNS settings without credentials. The dnscfg.cgi endpoint accepts direct unauthenticated requests and writes supplied primary or secondary DNS server values into device configuration. Network reachability to the web interface is sufficient, and successful modification redirects client DNS queries to attacker-controlled infrastructure.

The record

CVE
CVE-2026-0625
Published
Jan 5, 2026
Updated
Jan 5, 2026
Vendor
D-Link
Product
DSL-2640B
Classifications
CWE-306, T1565.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 27, 2025Exploitation reportedShadowserver exploitation observation
  2. Jan 5, 2026CVE publishedPublication date reported by the CVE source.
  3. Jan 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <=1.07

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

D-Link · DSL-2640Bversion=0 <=1.07
D-Link · DSL-2740Rversion=0 <1.17
D-Link · DSL-2780Bversion=0 <=1.01.14
D-Link · DSL-526Bversion=0 <=2.01

Published CVSS scores

9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1565.002Transmitted Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo