D-Link dnscfg.cgi Auth Bypass in DSL/DIR/DNS Router
CVE-2026-0625 Published on January 5, 2026
D-Link DSL/DIR/DNS Command Injection via DNS Configuration Endpoint
Multiple D-Link DSL/DIR/DNS devices contain an authentication bypass and improper access control vulnerability in the dnscfg.cgi endpoint that allows an unauthenticated attacker to access DNS configuration functionality. By directly requesting this endpoint, an attacker can modify the devices DNS settings without valid credentials, enabling DNS hijacking (DNSChanger) attacks that redirect user traffic to attacker-controlled infrastructure. In 2019, D-Link reported that this behavior was leveraged by the "GhostDNS" malware ecosystem targeting consumer and carrier routers. All impacted products were subsequently designated end-of-life/end-of-service, and no longer receive security updates. Exploitation evidence was observed by the Shadowserver Foundation on 2025-11-27 (UTC).
Weakness Type
Missing Authentication for Critical Function
The software does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Products Associated with CVE-2026-0625
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Affected Versions
D-Link DSL-2640B:- Version 0 is affected.
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- Version 0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.