CVE-2026-42375: CWE-798 Use of Hard-coded Credentials in D-Link DIR-600L Firmware
D-Link DIR-600L Hardware Revision A1 (End-of-Life) 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 "wrgn35_dlwbr_dir600l" read from /etc/alpha_config/image_sign. The custom telnetd binary accepts a -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.
AI Analysis
Technical Summary
CVE-2026-42375 identifies a critical vulnerability in the D-Link DIR-600L A1 firmware where a hardcoded telnet backdoor is present. The telnet daemon is launched at boot with a fixed username "Alphanetworks" and password "wrgn35_dlwbr_dir600l" stored in a configuration file. The authentication mechanism uses a simple string comparison, allowing an unauthenticated attacker on the local network to gain root shell access. This vulnerability is classified under CWE-798 (Use of Hard-coded Credentials). The device is End-of-Life, and no patches or official fixes are available.
Potential Impact
An attacker with local network access can exploit this vulnerability to gain root-level control over the affected device. This grants full administrative privileges, potentially allowing complete compromise of the device and any connected network resources. Because the device is End-of-Life, no vendor patches or updates will be provided to remediate this issue.
Mitigation Recommendations
Since the device is End-of-Life and no patches are available, mitigation options are limited. It is recommended to replace the affected hardware with a supported device that does not contain this vulnerability. Network segmentation to isolate the device and disabling telnet access if possible may reduce exposure. Monitor network access to the device and restrict local network access to trusted users only.
CVE-2026-42375: CWE-798 Use of Hard-coded Credentials in D-Link DIR-600L Firmware
Description
D-Link DIR-600L Hardware Revision A1 (End-of-Life) 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 "wrgn35_dlwbr_dir600l" read from /etc/alpha_config/image_sign. The custom telnetd binary accepts a -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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-42375 identifies a critical vulnerability in the D-Link DIR-600L A1 firmware where a hardcoded telnet backdoor is present. The telnet daemon is launched at boot with a fixed username "Alphanetworks" and password "wrgn35_dlwbr_dir600l" stored in a configuration file. The authentication mechanism uses a simple string comparison, allowing an unauthenticated attacker on the local network to gain root shell access. This vulnerability is classified under CWE-798 (Use of Hard-coded Credentials). The device is End-of-Life, and no patches or official fixes are available.
Potential Impact
An attacker with local network access can exploit this vulnerability to gain root-level control over the affected device. This grants full administrative privileges, potentially allowing complete compromise of the device and any connected network resources. Because the device is End-of-Life, no vendor patches or updates will be provided to remediate this issue.
Mitigation Recommendations
Since the device is End-of-Life and no patches are available, mitigation options are limited. It is recommended to replace the affected hardware with a supported device that does not contain this vulnerability. Network segmentation to isolate the device and disabling telnet access if possible may reduce exposure. Monitor network access to the device and restrict local network access to trusted users only.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- securin
- Date Reserved
- 2026-04-27T06:21:56.902Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f8cb08cbff5d86103668bd
Added to database: 5/4/2026, 4:36:24 PM
Last enriched: 5/4/2026, 4:51:41 PM
Last updated: 5/4/2026, 5:39:00 PM
Views: 4
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