D-Link DSL/DIR/DNS Authentication Bypass via DNS Configuration Endpoint
D-Link · DSL-2640B
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 device’s 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).
- Exploited
- Yes, in VulnCheck KEV
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited the day it was disclosed.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.
What security researchers reported
Not named in any threat report yetAlso mentioned in 1 community threat pulse (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.