D-Link DI-8100 Router Vulnerability: Remote Stack Buffer Overflow
The National Vulnerability Database has disclosed a critical stack-based buffer overflow vulnerability, CVE-2026-7851, affecting D-Link DI-8100 routers, specifically version 16.07.26A1. This flaw resides within the sprintf function in the yyxz.asp file. Attackers can remotely trigger this vulnerability by manipulating the ID argument, leading to arbitrary code execution or denial of service.
Rated with a CVSS score of 7.2 (HIGH), this vulnerability is particularly concerning because a public exploit is already available. This significantly lowers the barrier for attackers, allowing even less sophisticated actors to leverage it. The remote attack vector means threat actors don’t need local network access, expanding the potential attack surface for vulnerable devices connected to the internet.
For defenders, this is a clear and present danger. Routers are often overlooked attack vectors, yet they provide a direct pathway into internal networks. An attacker gaining control of a router can redirect traffic, eavesdrop on communications, or establish persistence. The public exploit availability means scanning and exploitation attempts are likely already underway.
What This Means For You
- If your organization or remote employees use D-Link DI-8100 routers (version 16.07.26A1), consider them immediately compromised or highly vulnerable. There's no patch currently mentioned, so immediate action means isolating these devices, replacing them, or placing them behind hardened firewalls with strict ingress filtering. Audit logs for any unusual activity on your network edge.
Related ATT&CK Techniques
🛡️ Detection Rules
2 rules · 6 SIEM formats2 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-7851 D-Link DI-8100 yyxz.asp Buffer Overflow
title: CVE-2026-7851 D-Link DI-8100 yyxz.asp Buffer Overflow
id: scw-2026-05-05-ai-1
status: experimental
level: critical
description: |
Detects attempts to exploit CVE-2026-7851 by targeting the yyxz.asp file with a POST request containing an 'ID=' parameter, indicative of a stack buffer overflow vulnerability in D-Link DI-8100 routers.
author: SCW Feed Engine (AI-generated)
date: 2026-05-05
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-7851/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri:
- '/yyxz.asp'
cs-method:
- 'POST'
cs-uri-query|contains:
- 'ID='
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-7851 | Buffer Overflow | D-Link DI-8100 version 16.07.26A1 |
| CVE-2026-7851 | Buffer Overflow | yyxz.asp file, sprintf function |
| CVE-2026-7851 | Buffer Overflow | Stack-based buffer overflow via manipulation of argument ID |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 05, 2026 at 21:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
Believe this infringes your rights? Submit a takedown request.
Related coverage
D-Link DI-8100 Buffer Overflow - CVE-2026-7855 Public Exploit Available
CVE-2026-7855 — A vulnerability was detected in D-Link DI-8100 16.07.26A1. Affected by this issue is the function tggl_asp of the file /tggl.asp of the component...
D-Link DI-8100 Critical Buffer Overflow (CVE-2026-7854)
CVE-2026-7854 — A security vulnerability has been detected in D-Link DI-8100 16.07.26A1. Affected by this vulnerability is the function url_rule_asp of the file /url_rule.asp of...
OpenStack Ironic Vulnerability CVE-2026-42997 Exposes Keystone Tokens
CVE-2026-42997 — An issue was discovered in idrac in OpenStack Ironic before 35.0.1. During import, a user invoking molds can request authorization to be sent...