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CVE Record

CVE-2021-34204: D-Link DIR-2640-US 1.01B04 is affected by Insufficiently Protected Credentials.

D-Link DIR-2640-US 1.01B04 is affected by Insufficiently Protected Credentials. D-Link AC2600(DIR-2640) stores the device system account password in plain text. It does not use linux user management. In addition, the passwords of all devices are the same, and they cannot be modified by normal users. An attacker can easily log in to the target router through the serial port and obtain root privileges.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-34204 describes a D-Link DIR-2640-US firmware issue where the router system account password is stored in plaintext and appears shared across devices. The stated impact is root access through the serial port. The public record does not show active exploitation or a CVSS score.

Executive priority

Treat this as a targeted device-risk issue, not broad internet-facing emergency based on current evidence. Prioritize inventory confirmation, vendor guidance, and physical-security controls for any matching routers.

Technical view

The CVE description says D-Link DIR-2640-US 1.01B04 does not use Linux user management and stores the device system account password in plaintext. It also says normal users cannot modify these shared passwords. Reported access path is serial-port login leading to root privileges.

Likely exposure

Exposure appears limited to D-Link DIR-2640-US 1.01B04 devices, based on the CVE description. The official affected-product metadata is incomplete, so confirm firmware and model from inventory rather than assuming broader D-Link impact.

Exploitation context

CISA KEV is false in the provided bundle, and no cited source states active exploitation. The described attack requires serial-port access to the target router; the bundle does not describe a remote network exploitation path.

Researcher notes

The source bundle lacks CVSS, CWE, complete affected CPE data, and explicit vendor remediation details. The strongest evidence is the CVE description and linked public researcher report; avoid expanding scope beyond DIR-2640-US 1.01B04 without vendor confirmation.

Mitigation direction

  • Identify any deployed D-Link DIR-2640-US routers and record firmware versions.
  • Check D-Link security bulletins for model-specific firmware or retirement guidance.
  • Restrict physical access to routers, labs, closets, and shipping workflows.
  • Replace affected devices if no vendor-supported remediation is available.
  • Avoid assuming password rotation fixes this, because the CVE says normal users cannot modify it.

Validation and detection

  • Confirm whether any inventory item is D-Link DIR-2640-US firmware 1.01B04.
  • Review asset records for unmanaged routers or lab devices matching this model.
  • Check vendor advisories for a fixed firmware version or product status.
  • Validate physical controls around locations where affected routers are installed.
  • Document uncertainty where asset metadata cannot confirm model or firmware.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2021-34204 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
1ADP providers
3Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.