CVE-2026-10270: D-Link DI-7001 Buffer Overflow Vulnerability

CVE-2026-10270 Overview

CVE-2026-10270 is a stack-based buffer overflow vulnerability affecting D-Link DI-7001 MINI routers running firmware up to version 19.09.19A1. The flaw resides in the sprintf function call within the /httpd_debug.asp API endpoint, where manipulation of the Time argument triggers memory corruption on the stack. The vulnerability is exploitable remotely over the network and requires only low-privileged authentication. Public exploit details have been disclosed, increasing the risk of opportunistic attacks against exposed devices. The weakness is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer).

Critical Impact

Remote attackers with low-privileged access can corrupt stack memory on affected D-Link routers, potentially leading to arbitrary code execution or device compromise.

Affected Products

• D-Link DI-7001MINI-8G hardware revision A1
• D-Link DI-7001MINI-8G firmware version 19.09.19A1 and earlier
• D-Link DI-7001 MINI API component (/httpd_debug.asp)

Discovery Timeline

• 2026-06-01 - CVE-2026-10270 published to NVD
• 2026-06-03 - Last updated in NVD database

Technical Details for CVE-2026-10270

Vulnerability Analysis

The vulnerability exists in the HTTP debug interface exposed at /httpd_debug.asp on the D-Link DI-7001 MINI router. The handler processes a user-controlled Time parameter and passes it to the C standard library sprintf function without enforcing length validation against the destination buffer. Because sprintf performs no bounds checking, oversized input overflows the fixed-size stack buffer, overwriting adjacent stack frames including the saved return address.

An attacker reaching the API endpoint over the network can deliver a crafted request that corrupts execution flow on the embedded device. According to the public disclosure, exploit material is already available, and the attack complexity is low. The Time parameter sits in a debug-related endpoint, which suggests minimal hardening compared to production-facing handlers.

Root Cause

The root cause is unsafe use of the sprintf function on attacker-controlled input. D-Link's firmware does not validate the length of the Time argument before formatting it into a stack-allocated buffer. Safer alternatives such as snprintf with explicit size limits would have prevented the overflow. This is a classic [CWE-119] memory safety failure common in embedded MIPS and ARM router firmware compiled without modern stack protections.

Attack Vector

Exploitation requires network reachability to the router's management interface and a valid low-privilege session. An attacker sends an HTTP request to /httpd_debug.asp containing an oversized Time parameter. The malformed request triggers the overflow within the request handler, allowing the attacker to overwrite saved registers and the return address on the stack. On embedded devices lacking ASLR, NX, or stack canaries, this typically leads to arbitrary code execution with the privileges of the web server process — often root.

No verified proof-of-concept code is reproduced here. See the GitHub PoC Repository and VulDB entry for CVE-2026-10270 for technical artifacts.

Detection Methods for CVE-2026-10270

Indicators of Compromise

• HTTP requests targeting /httpd_debug.asp with abnormally long Time parameter values, particularly exceeding typical timestamp string lengths.
• Unexpected reboots, crashes, or httpd process restarts on D-Link DI-7001 MINI devices coinciding with inbound web traffic.
• Outbound connections from the router to unfamiliar hosts following access to debug endpoints, indicating post-exploitation activity.
• Authentication log entries showing low-privilege account access followed by access to the debug API path.

Detection Strategies

• Inspect HTTP traffic to router management interfaces for requests to /httpd_debug.asp containing the Time parameter and flag entries exceeding a conservative length threshold.
• Deploy IDS/IPS signatures that match oversized query strings or POST bodies directed at known D-Link debug endpoints.
• Correlate router-side syslog events showing httpd segmentation faults or watchdog-triggered reboots with prior web requests to the debug API.

Monitoring Recommendations

• Forward router syslog and authentication events to a centralized log platform and alert on anomalous access patterns to /httpd_debug.asp.
• Monitor north-south and east-west traffic from router management interfaces for unexpected outbound connections that could indicate post-exploitation command-and-control.
• Track firmware versions across the fleet and alert when devices report version 19.09.19A1 or earlier.

How to Mitigate CVE-2026-10270

Immediate Actions Required

• Restrict access to the router management interface to trusted internal management VLANs and remove any exposure to the public internet.
• Disable or block access to the /httpd_debug.asp endpoint at the network perimeter or via an upstream firewall ACL.
• Rotate credentials for all administrative and low-privilege accounts on affected devices, since the attack requires only low-privilege authentication.
• Inventory all D-Link DI-7001 MINI devices and identify those running firmware 19.09.19A1 or earlier for prioritized remediation.

Patch Information

At the time of publication, no vendor advisory or patched firmware release has been linked to CVE-2026-10270 in the NVD record. Administrators should monitor the D-Link Official Website and the VulDB entry for CVE-2026-10270 for updates. Until a patched firmware is available, compensating controls are required.

Workarounds

• Place affected routers behind a segmentation firewall and permit management traffic only from a dedicated jump host.
• Apply ACLs on the router itself, where supported, to limit HTTP/HTTPS management access to specific source IP addresses.
• Disable remote management features and ensure WAN-side administrative access is turned off.
• If the device is not business-critical, consider decommissioning or replacing it with a supported model until a firmware fix is released.

# Example upstream firewall rule to block external access to the vulnerable debug endpoint
# (adapt syntax to your firewall platform)
iptables -A FORWARD -p tcp --dport 80 -d <router_ip> \
  -m string --string "/httpd_debug.asp" --algo bm -j DROP
iptables -A FORWARD -p tcp --dport 443 -d <router_ip> \
  -m string --string "/httpd_debug.asp" --algo bm -j DROP