CVE-2021-25309

Administrative access via unthrottled four-digit passcode guessing

Published Mar 2, 2021 · Updated Aug 3, 2024

Weak authentication in Gigaset DX600A 41.00-175 allows remote attackers to gain administrative access through Telnet passcode guessing. The administrator service on TCP port 650 accepts repeated attempts without lockout or throttling while restricting the passcode to four digits. Access requires network reachability to that service, and a successful guess exposes contacts, call records, messages, and complete device configuration.

CVSS severity8.8
High
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak authentication in Gigaset DX600A 41.00-175 allows remote attackers to gain administrative access through Telnet passcode guessing. The administrator service on TCP port 650 accepts repeated attempts without lockout or throttling while restricting the passcode to four digits. Access requires network reachability to that service, and a successful guess exposes contacts, call records, messages, and complete device configuration.

The record

CVE
CVE-2021-25309
Published
Mar 2, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-307, CWE-521, T1110
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 vectoradjacent
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
8.8NCC GroupCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
CWE-521Weak Password Requirements
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

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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