Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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ReconObtain admin credentials
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DeliveryAuthenticate to web interface
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ExploitSend crafted request to yyxz.asp
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InstallOverflow stack buffer via ID parameter
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C2Overwrite return address
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ExecuteExecute arbitrary code as root
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ImpactEstablish persistence or pivot
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Requires valid administrative credentials (PR:H in CVSS vector) to access the D-Link DI-8100 web management interface. The vulnerable yyxz.asp endpoint is part of the authenticated admin panel, not publicly accessible without login. Network connectivity to the management interface is required (AV:N), which may be LAN-only in secure deployments or internet-exposed in misconfigured installations. No user interaction is needed post-authentication (UI:N). Exploitation is limited by credential access-default passwords, weak passwords, or compromised admin accounts are the enabling factor. Organizations restricting management to isolated VLANs with strong authentication significantly reduce practical exploitability despite low attack complexity once authenticated. |
| Impact | Real-world risk is elevated but scope-limited. CVSS 7.3 High severity reflects complete system compromise (VC:H/VI:H/VA:H) via network vector (AV:N) with low complexity (AC:L), but critically requires high-privilege authentication (PR:H)-typically admin credentials. The E:P (Proof-of-concept) metric confirms working exploit code exists on GitHub. However, no EPSS score or CISA KEV data is provided in intelligence sources, suggesting exploitation is not yet widespread despite POC availability. Attack complexity is low once authenticated, but the high privilege requirement significantly constrains attacker population to credential theft scenarios, phishing victims, or malicious insiders. Enterprise defenders should prioritize this for internet-facing management interfaces or environments with weak credential hygiene, but lower priority where admin access is properly restricted to trusted networks with MFA enforced. The device appears to be older enterprise hardware; confirm if still in production use before resource allocation. |
| Exploit ScenarioDerived | An attacker obtains D-Link DI-8100 administrative credentials through phishing, credential stuffing, or default password reuse. They authenticate to the web management interface over the network and craft an HTTP request to yyxz.asp with an oversized ID parameter (e.g., 2000+ byte payload containing shellcode). The sprintf() call overflows the stack buffer, overwriting the return address to redirect execution to attacker-controlled code. The attacker achieves root-level code execution on the router, enabling installation of persistent backdoors, traffic interception, or pivoting to internal network segments. |
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Alert meAnalysisAIv1 – May 05, 2026
Stack-based buffer overflow in D-Link DI-8100 router firmware 16.07.26A1 allows authenticated remote attackers with high privileges to execute arbitrary code via malformed ID parameter to yyxz.asp administrative interface. Public exploit code exists on GitHub, demonstrating reliable exploitation. CVSS 7.3 (High) reflects network attack vector but requires admin-level authentication, limiting real-world exposure to compromised credentials or insider scenarios.
RemediationAI
Check D-Link support portal (https://www.dlink.com/) and product-specific firmware pages for security updates addressing CVE-2026-7851; as of analysis time, no vendor advisory or patched firmware version is confirmed in provided references. If no patch is available and device remains in production, implement defense-in-depth: (1) Restrict administrative interface access to trusted management VLANs only-block WAN access entirely and prohibit internet exposure; (2) Enforce strong authentication with complex passwords rotated quarterly and enable multi-factor authentication if supported; (3) Monitor admin access logs for unusual login patterns or access to yyxz.asp endpoint; (4) If feasible, consider hardware replacement with actively supported models as DI-8100 may be end-of-life. Trade-off: Network-level access restrictions do not prevent exploitation by compromised admin accounts but significantly reduce attack surface from external threats.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The vulnerability resides in yyxz.asp, an administrative web interface component of D-Link DI-8100 enterprise router firmware. The unsafe sprintf() function performs unbounded string copying of user-controlled ID parameter data into a fixed-size stack buffer without length validation. This is a classic CWE-121 stack-based buffer overflow pattern common in legacy C/C++ embedded device firmware. When input exceeds buffer capacity, adjacent stack memory-including return addresses and frame pointers-is overwritten, enabling control-flow hijacking. The DI-8100 is an enterprise-grade multi-WAN load-balancing router; exploitation requires access to the web management interface typically restricted to internal networks or VPN-connected administrators.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
Primary rating from Vendor (VulDB) · only source for this CVE.
CVSS VectorVendor: VulDB
Lifecycle Timeline
1DescriptionCVE.org
A vulnerability was identified in D-Link DI-8100 16.07.26A1. This affects the function sprintf of the file yyxz.asp. The manipulation of the argument ID leads to stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit is publicly available and might be used.
Executive ViewAI
D-Link DI-8100 router firmware 16.07.26A1 contains a stack-based buffer overflow vulnerability in the administrative interface that allows authenticated administrators to execute arbitrary code on the device. While the vulnerability requires admin-level credentials to exploit, the availability of public exploit code and lack of vendor patch creates a material risk for organizations using this router model, particularly in environments where admin accounts may be compromised or insider threats exist.
Since no vendor-released patch is currently available: (1) Restrict admin-level access to DI-8100 devices to a minimal set of trusted administrators only; (2) Implement network-level controls to limit access to the yyxz.asp administrative interface via IP whitelisting or firewall rules; (3) Monitor administrative logs on affected routers for unusual parameter patterns or failed access attempts; (4) Segment administrative management traffic onto a dedicated, protected management network isolated from user data traffic; (5) Establish a vendor follow-up schedule to confirm patch release timeline and plan remediation accordingly.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
Remote unauthenticated buffer overflow in D-Link DI-8100 firmware 16.07.26A1 enables attackers to execute arbitrary code
Buffer overflow in D-Link DI-8100 router firmware 16.07.26A1 allows remote unauthenticated attackers to execute arbitrar
Buffer overflow in D-Link DI-8100 router (firmware 16.07.26A1) allows authenticated remote attackers to execute arbitrar
Buffer overflow in D-Link DI-8100 router firmware 16.07.26A1 enables authenticated remote code execution via crafted inp
Buffer overflow in D-Link DI-8100 router firmware 16.07.26A1 allows authenticated administrators to execute arbitrary co
EUVD-2026-27416
GHSA-x4pj-ppv6-g6w7
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB