VulnerabilityPublished 25 Aug 2025Updated 26 Aug 2025

CVE-2025-29521: Use of Default Credentials

Source CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Immediate verification and change of default administrator credentials on all affected D-Link DSL-7740C devices to strong, unique passwords.
Restrict remote administrative access to trusted IP addresses or disable remote management entirely if not needed.
Implement network segmentation to isolate management interfaces from general user networks and the internet.
Monitor device logs for repeated failed login attempts indicative of brute-force attacks.
Where possible, upgrade firmware to a version that addresses this vulnerability once available from D-Link.
Employ network-level protections such as intrusion detection/prevention systems (IDS/IPS) to detect and block brute-force attempts targeting router management interfaces.
Conduct regular audits of network devices to ensure no default credentials remain in use and that security best practices are enforced.
Educate network administrators about the risks of default credentials and the importance of secure configuration management.

Description

Insecure default credentials for the Adminsitrator account of D-Link DSL-7740C with firmware DSL7740C.V6.TR069.20211230 allows attackers to escalate privileges via a bruteforce attack.

Impact

For European organizations, this vulnerability poses a moderate risk primarily to those using the D-Link DSL-7740C router with the specified firmware version. Successful exploitation could lead to unauthorized administrative access, enabling attackers to manipulate network settings, potentially intercept sensitive communications, or pivot to internal systems. This could compromise confidentiality of data traversing the network and undermine trust in network infrastructure. While the vulnerability does not directly impact integrity or availability, the administrative control gained could be leveraged for further malicious activities, including deploying malware or establishing persistent access. Organizations in sectors with high data sensitivity or regulatory requirements (e.g., finance, healthcare, government) could face compliance risks and reputational damage if exploited. The lack of required authentication and user interaction increases the likelihood of automated brute-force attacks, especially if devices are exposed to the internet or poorly segmented internal networks.

CWE-1392Use of Default Credentials (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product uses default credentials (such as passwords or cryptographic keys) for potentially critical functionality.
Requirements
Prohibit use of default, hard-coded, or other values that do not vary for each installation of the product - especially for separate organizations.
Architecture and Design
Force the administrator to change the credential upon installation.
Installation · Operation
The product administrator could change the defaults upon installation or during operation.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 2 Sep 2025, 01:06 UTC

WeaknessesCWE-1392

Technical details

References

Community reviews

Related threats