Cyber Resilience

CVE-2025-29521

Dlink Dsl-7740C Firmware 6.tr069.20211230

Public PoC
Published
25 August 2025
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS Score 0.0059 46th percentile
Risk Priority 45 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2025-29521 is a medium-severity Use of Default Credentials (CWE-1392) vulnerability in Dlink Dsl-7740C Firmware. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Default Accounts (T1078.001); ranked at the 46th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and IA-5 (Authenticator Management) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-1392

Related Threats

MITRE ATT&CK Enterprise Techniques

T1078.001 Default Accounts Stealth
Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1021 Remote Services Lateral Movement
Adversaries may use [Valid Accounts](https://attack.
attack.mitre.org →
T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-29520Same product: Dlink Dsl-7740C
CVE-2025-29515Same product: Dlink Dsl-7740C
CVE-2025-29514Same product: Dlink Dsl-7740C
CVE-2025-29519Same product: Dlink Dsl-7740C
CVE-2025-29517Same product: Dlink Dsl-7740C
CVE-2025-29523Same product: Dlink Dsl-7740C
CVE-2025-29516Same product: Dlink Dsl-7740C
CVE-2025-29522Same product: Dlink Dsl-7740C
CVE-2024-5245Shared CWE-1392
CVE-2023-49621Shared CWE-1392

Affected Assets

dlink
dsl-7740c firmware
6.tr069.20211230

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V13.2.1

Mitigating Controls (NIST 800-53 r5) AI

CM-6 Configuration Settings good match

Secure configuration settings establish baselines that prohibit default credentials on system components.

IA-5 Authenticator Management good match

Authenticator management requires verification of identity and secure distribution of initial authenticators, directly stopping default credentials from being left in place.

RA-5 Vulnerability Monitoring and Scanning good match

Vulnerability scanning can discover default credentials after deployment but does not stop their introduction.

AC-2 Account Management partial match

Account management processes include assignment and control of initial account credentials, reducing the chance defaults remain active.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-01 full match
prevents

Hardened baselines and configuration management explicitly prohibit default credentials on deployed systems.

PR.AA-01 mostly match
prevents

Credential management processes directly require replacing or disabling default passwords and keys.

PR.AA-03 partial match
prevents

Authentication policies can enforce non-default credential strength but do not explicitly address initial deployment defaults.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.9 Configuration management mostly match
prevents

The requirement to replace vendor default authentication information immediately after installation directly counters the use of default credentials that attackers commonly target.

References