Cyber Resilience

CVE-2023-39086

Asus Rt-Ac66U B1 Firmware 3.0.0.4.286_51665

Published
08 August 2023
Modified
09 July 2026
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0037 30th percentile
Risk Priority 57 floored blend · peak EPSS

Summary

CVE-2023-39086 is a high-severity Cleartext Transmission of Sensitive Information (CWE-319) vulnerability in Asus Rt-Ac66U B1 Firmware. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Sniffing (T1040); ranked at the 30th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

ASUS RT-AC66U B1 3.0.0.4.286_51665 was discovered to transmit sensitive information in cleartext.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1040 Network Sniffing Credential Access
Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-31195Same vendor: Asus
CVE-2025-62330Shared CWE-319
CVE-2025-0432Shared CWE-319
CVE-2024-35495Shared CWE-319
CVE-2025-36034Shared CWE-319
CVE-2025-2818Shared CWE-319
CVE-2024-35057Shared CWE-319
CVE-2023-23915Shared CWE-319
CVE-2023-29680Shared CWE-319
CVE-2025-32887Shared CWE-319

Affected Assets

asus
rt-ac66u b1 firmware
3.0.0.4.286_51665

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-319

Role-based training covers secure transmission methods, mitigating cleartext transmission of sensitive data.

addresses: CWE-319

By requiring documented security controls for information exchanges, the control reduces the risk of cleartext transmission of sensitive data.

addresses: CWE-319

Mapping transmission actions in data flows helps prevent cleartext transmission of sensitive information.

addresses: CWE-319

Settings can enforce secure transmission protocols to prevent cleartext transmission of sensitive data.

addresses: CWE-319

Policy addresses secure transport and handling of media to avoid cleartext transmission of sensitive information.

addresses: CWE-319

Enforces safeguards against cleartext transmission of CUI when data leaves organizational boundaries to external systems.

addresses: CWE-319

Explicit controls and continuous oversight on external system services prevent cleartext transmission of sensitive information over provider-managed channels.

addresses: CWE-319

Key-establishment procedures specify secure distribution channels that preclude cleartext transmission of key material.

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.DS-02 full match
prevents

Encryption of data-in-transit directly prevents cleartext transmission while the control also addresses integrity and availability.

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.

prevents

Specifying encryption and other security technology for network services prevents transmission of sensitive information in cleartext over potentially untrusted channels.

prevents

Mandating cryptographic protection and stronger authentication on public networks stops the transmission of plaintext sensitive information.

mitigates

Specifying communications-security requirements and secure remote-access methods (including encryption expectations) prevents the transmission of sensitive data in cleartext over home or public networks.

mitigates

Armoured conduits, electromagnetic shielding and locked enclosures make passive eavesdropping on unencrypted traffic traversing the cables more difficult, mitigating exposure of sensitive data in transit.

References