What is the CVSS score of CVE-2026-91003?

CVE-2026-91003 has a CVSS 4.0 base score of 8.5 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2026-91003?

Yes, a public proof-of-concept exploit is available for CVE-2026-91003. Prioritise patching immediately. EPSS: 0.5%.

Di 8300 CVE-2026-91003

EUVD-2026-78278 HIGH

Stack-based Buffer Overflow (CWE-121)

2026-09-15 VulDB

GHSA-p599-cqm7-c2xh

Buffer Overflow D-Link Stack Overflow D-Link Di 8300

8.5

CVSS 4.0 · Vendor: VulDB

View

Vulnerability Assessment

Weakness

CWE

CWE-121

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.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

1 PoC candidate (unverified) No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 15, 2026

Stack-based buffer overflow in the rzgl_asp CGI handler of D-Link DI-8300 firmware 16.07 lets a remote attacker who can reach the device's web management interface (and, per the CVSS vector, holds high/admin privileges) crash or execute code on the router by supplying an oversized redirct_url parameter to /rzgl.asp. Publicly available exploit code exists, so the vulnerability is trivially reproducible, although no CISA KEV listing or confirmed in-the-wild campaign is reported. The device is a legacy D-Link gateway, and no vendor patch or advisory was found in the supplied references.

Affected VersionsENISA

DI-8300 16.07

Affected Packages

euvd di_8300 no fix

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.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulDB) PRIMARY 8.5 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

Primary rating from Vendor (VulDB) · only source for this CVE.

CVSS VectorVendor: VulDB

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

High

User Interaction

None

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

High

Vulnerable system: Availability

High

Subsequent system: Confidentiality

High

Subsequent system: Integrity

High

Subsequent system: Availability

High

Lifecycle Timeline

Severity Changed

Sep 15, 2026 - 06:22 NVD

CRITICAL HIGH

CVSS changed

Sep 15, 2026 - 06:22 NVD

9.4 (CRITICAL) 8.5 (HIGH)

CVE Published

Sep 15, 2026 - 05:45 cve.org

HIGH 8.5

DescriptionCVE.org

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.

Technical POC Analysis

Evidence note: the supplied artifact is labelled "PATCHED SOURCE rzgl/rzglasp.py", but its contents are an exploit client (imports requests/base64, POSTs to a target), not a source diff.

Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.

Latest POC

1 PoC candidate from github (unverified)

Threat Intelligence Overview

EPSS Score

0.5%

Top 58% exploitable

Social Media

Sightings

Data Quality

7 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS

Vulnrichment CIRCL

GitHub

VulDB

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.

SignalValue

Severity HIGH

CISA KEV No

Public POC Yes

EPSS 0.5%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation

Poc

System Exposure· derived

Open

Automatable

Human Impact· derived

Medium

Technical Impact

Total

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +42

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

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.

Stack-based Buffer Overflow HIGH

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.