CVE Alert: CVE-2025-11339 – D-Link – DI-7100G C1

Risk verdict

High risk due to remote buffer overflow in jhttpd with publicly disclosed exploit; exploitation can occur without user interaction.

Why this matters

The vulnerability enables remote code execution on the device, potentially yielding full control, data exposure, and disruption of network services. In environments where DI-7100G C1 provides gateway or management access, an attacker could pivot to other network assets and impair business continuity.

Most likely attack path

Attack begins with a crafted request to /webchat/hi_block.asp using a manipulated popupId, exploiting a memory corruption flaw. No user interaction is required and the attacker needs only low privileges on the device to trigger the flaw; successful exploitation yields high-impact C/I/A damage. Given AV:N and UI:N, exploitation is straightforward from remote locations if the device is reachable from the attacker’s network, increasing lateral-movement risk within exposed network segments.

Who is most exposed

Devices deployed in SMB/branch networks with exposed management interfaces or default/weak access controls are particularly at risk; environments using this legacy D-Link gateway/voice-access setup are most vulnerable.

Detection ideas

• Unusual spikes in processor load or crashes tied to /webchat/hi_block.asp requests
• Repeated or malformed requests targeting popupId parameters in jhttpd logs
• Memory corruption indicators: abnormal core dumps, reboot loops, or service restarts
• IDS/IPS signatures for known PoC patterns related to this CVE
• Anomalous authentication attempts to the device’s management interface

Mitigation and prioritisation

• Apply vendor patch/firmware update (20250928 or newer) as a priority as soon as available
• Disable or restrict remote management exposure; implement network segmentation and allow management only from trusted nets
• Enforce strong access controls and rotate credentials; monitor for unusual admin activity
• If patching is delayed, implement compensating controls: firewall rules, WAF/IPS where feasible, and strict egress monitoring
• Change-management: schedule a patch window, test in a staging segment, and verify post-update health
• Treat as priority 1 if KEV or EPSS ≥ 0.5 is confirmed through authoritative feeds (not assumed here)