CVE-2026-42373
Exposed Creds in Dlink Dir-605L Firmware
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-42373 is a critical-severity Use of Hard-coded Credentials (CWE-798) vulnerability in Dlink Dir-605L Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Unsecured Credentials (T1552); ranked at the 39th 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 IA-5 (Authenticator Management) and SC-12 (Cryptographic Key Establishment and Management) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-42373 is a hardcoded credential vulnerability (CWE-798) in the D-Link DIR-605L Hardware Revision B2 router, an end-of-life (EOL) device. The flaw involves a telnet backdoor daemon launched at boot via the /bin/telnetd.sh script, which configures the service with a static username of "Alphanetworks" and password "wrgn76_dlwbr_dir605L" sourced from /etc/alpha_config/image_sign. A custom telnetd binary accepts a -u user:password flag, while the custom login binary performs credential validation using strcmp(). The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
An unauthenticated attacker with access to the local network can exploit this by connecting to the telnet service using the hardcoded credentials, gaining a root shell with full administrative control over the device.
Advisories, including those published by Securin at https://www.securin.io/zero-day/cve-2026-42373-hardcoded-telnet-backdoor-in-d-link-dir-605l-b2-end-of-life-, confirm the device is EOL and will not receive patches from D-Link. Mitigation requires isolating affected devices from untrusted networks or decommissioning them entirely, as no firmware updates are available.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-27023
Vulnerability Data
D-Link DIR-605L Hardware Revision B2 (End-of-Life, EOL) contains a hardcoded telnet backdoor. The device starts a telnet daemon at boot via /bin/telnetd.sh with the username "Alphanetworks" and the static password "wrgn76_dlwbr_dir605L" read from /etc/alpha_config/image_sign. The custom telnetd binary accepts a…
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-u user:password flag, and the custom login binary uses strcmp() to validate credentials. Successful authentication grants an unauthenticated attacker on the local network a root shell with full administrative control. The device has reached End-of-Life (EOL) and will not receive patches.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Authenticator management requires secure distribution and handling of credentials, structurally discouraging hard-coded values.
Cryptographic key management mandates proper establishment and handling instead of embedding keys in code.
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.AA-01's credential/key-management processes can reduce the incentive to embed secrets but do not address or detect hard-coded values in source code, so the weakness remains fully possible.
PR.AA-02 addresses human identity proofing and per-person credential issuance at enrollment; it has no bearing on whether developers embed static credentials in software.
PR.DS-01 addresses encryption and integrity of stored data but never touches credential or key management practices, so it neither prevents hard-coded credentials nor removes any of their risk.
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.
Education on secure configuration practices discourages technical staff from embedding or relying on hard-coded credentials in systems and applications.
Secure key-generation, distribution and storage procedures reduce the likelihood that hard-coded or default cryptographic keys will be introduced or left unprotected.
Explicit prohibition of hard-coded passwords and unauthenticated external services stops credentials from being embedded directly in source code.
Contractual requirements for secure coding practices and evidence of testing make it less likely that hard-coded credentials will be introduced or remain undetected in delivered code.
Requiring independent oversight and timely disabling of non-human identities makes it harder for hard-coded or long-lived credentials to remain exploitable.
Mandating immediate replacement of vendor-supplied default credentials eliminates the use of hard-coded or factory passwords that attackers can trivially obtain from documentation or firmware.