CVE-2021-39615Public exploitNetwork attack vector

Unauthorized device access via hard-coded account

Published Aug 23, 2021 · Updated Aug 4, 2024

Hard-coded credentials in D-Link DSR-500N 1.02 allow remote attackers to gain device access through SSH or Telnet. An undocumented root-capable account is embedded as a password hash in /etc/passwd, and recovering its cleartext password enables a valid login. Exploitation requires network reachability to SSH or Telnet and recovery of the stored hash's cleartext value; successful access grants control of the embedded Linux operating system.

CVSS severity9.8
Critical
EPSS probability2.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hard-coded credentials in D-Link DSR-500N 1.02 allow remote attackers to gain device access through SSH or Telnet. An undocumented root-capable account is embedded as a password hash in /etc/passwd, and recovering its cleartext password enables a valid login. Exploitation requires network reachability to SSH or Telnet and recovery of the stored hash's cleartext value; successful access grants control of the embedded Linux operating system.

The record

CVE
CVE-2021-39615
Published
Aug 23, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-798, T1078.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
T1078.001Valid Accounts: Default Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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