CVE-2026-91003
Received Received - Intake

Stack-Based Buffer Overflow in D-Link DI-8300 Router

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: VulDB

Description
A flaw has been found in D-Link DI-8300 16.07. The affected element is the function rzgl_asp of the file /rzgl.asp of the component CGI Service. This manipulation of the argument redirct_url causes stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit has been published and may be used.

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Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
CVE-2026-91003
EUVD
EUVD-2026-78278

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
d-link di-8300 16.07

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

Attack-Flow Graph

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Executive Summary

CVE-2026-91003 is a stack-based buffer overflow in D-Link DI-8300 firmware 16.07. The flaw exists in the rzgl_asp function of the CGI Service, specifically when processing the redirct_url parameter. Attackers can send a maliciously crafted payload exceeding 1366 bytes (Base64-encoded) that overflows stack buffers, potentially allowing arbitrary code execution. Exploitation requires administrator authentication but can lead to full device compromise.

Detection Guidance

To detect this vulnerability, monitor network traffic for POST requests to /rzgl.asp with unusually long redirct_url parameters. Check for Base64-encoded payloads exceeding 1366 bytes or decoded payloads over 1024 bytes. Inspect logs for crashes or unresponsive services after such requests.

Impact Analysis

This vulnerability allows remote attackers to execute arbitrary code on the affected device. Successful exploitation could result in administrative takeover, credential theft, and persistent denial-of-service attacks. Attackers may gain full control over the device, including network access restrictions and sensitive data exposure.

Mitigation Strategies

Immediately restrict network access to the vulnerable device, especially from untrusted sources. Update the firmware if a patch is available. Implement input length validation for the redirct_url parameter and replace unsafe string functions like strcat with safer alternatives.

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