HOMEVULNERABILITIESCVE-2021-25309
CRITICAL

CVE-2021-25309

CWE-307Published: March 2, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

The telnet administrator service running on port 650 on Gigaset DX600A v41.00-175 devices does not implement any lockout or throttling functionality. This situation (together with the weak password policy that forces a 4-digit password) allows remote attackers to easily obtain administrative access via brute-force attacks.

NVD Source

Technical Analysis

CVE-2021-25309 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

gigaset2 product(s)
dx600a firmwaredx600a
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://research.nccgroup.com/2021/02/28/technical-advisory-administrative-passcode-recovery-and-authenticated-remote-buffer-overflow-vulnerabilities-in-gigaset-dx600a-handset-cve-2021-25309-cve-2021-25306/
ADVISORYhttps://research.nccgroup.com/2021/02/28/technical-advisory-administrative-passcode-recovery-and-authenticated-remote-buffer-overflow-vulnerabilities-in-gigaset-dx600a-handset-cve-2021-25309-cve-2021-25306/

All References (2)

→
https://research.nccgroup.com/2021/02/28/technical-advisory-administrative-passcode-recovery-and-authenticated-remote-buffer-overflow-vulnerabilities-in-gigaset-dx600a-handset-cve-2021-25309-cve-2021-25306/Third Party Advisory
→
https://research.nccgroup.com/2021/02/28/technical-advisory-administrative-passcode-recovery-and-authenticated-remote-buffer-overflow-vulnerabilities-in-gigaset-dx600a-handset-cve-2021-25309-cve-2021-25306/Third Party Advisory

Quick Facts

CVE IDCVE-2021-25309
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-307
CISA KEVNo
Affected1 vendor(s)
PublishedMar 2, 2021

Related CVEs (CWE-307)

CVE-2021-37934
9.8
CVE-2020-21237
9.8
CVE-2021-38474
9.8
CVE-2021-41435
9.8
CVE-2021-42544
9.8
CVE-2020-21238
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-25309 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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