Cyber Resilience

CVE-2021-34203

HighPublic PoC

Published: 16 June 2021

Published
16 June 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0007 21.3th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-34203 is a high-severity Initialization of a Resource with an Insecure Default (CWE-1188) vulnerability in Dlink Dir-2640-Us Firmware. Its CVSS base score is 8.1 (High).

Operationally, ranked at the 21.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

This vulnerability is AI-related — categorised as Other AI Platforms.

EU & UK References

Vulnerability details

D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control. Router ac2600 (dir-2640-us), when setting PPPoE, will start quagga process in the way of whole network monitoring, and this function uses the original default password and port. An attacker can easily…

more

use telnet to log in, modify routing information, monitor the traffic of all devices under the router, hijack DNS and phishing attacks. In addition, this interface is likely to be questioned by customers as a backdoor, because the interface should not be exposed.

CWE(s)

AI Security AnalysisAI

AI Category
Other AI Platforms
Risk Domain
N/A
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: backdoor

Related Threats

Affected Assets

dlink
dir-2640-us firmware
1.01b04

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-1188

Requires documented secure initialization practices and avoidance of insecure defaults in configuration baselines.

addresses: CWE-1188

Reviewing and updating baseline when components are installed or upgraded prevents initialization with insecure defaults.

addresses: CWE-1188

Requiring explicit configuration to minimal functionality overrides insecure defaults that would otherwise enable excess capabilities.

addresses: CWE-1188

Tailoring replaces or augments insecure default initializations with system-specific values and compensating controls before deployment.

addresses: CWE-1188

Central configuration overrides or replaces insecure default initializations that would otherwise be left unchanged on each system.

addresses: CWE-1188

SCRM practices during acquisition and configuration management address insecure default initializations shipped by vendors.

addresses: CWE-1188

Scans detect resources initialized with insecure defaults that create exploitable conditions.

addresses: CWE-1188

Instruction on secure initialization of security controls prevents leaving resources with insecure defaults after installation.

References