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TI-2026-30675 Aliases CVE-2026-42375GHSA-rgp4-f9jj-fjwc

D-Link DIR-600L A1 Hardcoded Telnet Backdoor Credentials

Priority HIGH 76CWE-798Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-798.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00472 41st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
D-LinkDIR-600L FirmwareA1 and later—No fix listedCNA
  • DIR-600L Firmware VendorD-Link Affected A1 and later Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:dlink:dir-600l_firmware:*:*:*:*:*:*:*:*all versionsVulnerableD-Link Japan K.K.
cpe:2.3:h:dlink:dir-600l:a1:*:*:*:*:*:*:*a1Running onD-Link Japan K.K.
  • cpe:2.3:o:dlink:dir-600l_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·D-Link Japan K.K.
  • cpe:2.3:h:dlink:dir-600l:a1:*:*:*:*:*:*:* Versions a1 Running on ·D-Link Japan K.K.

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42375
  2. 2026-10-03 Alias added: GHSA-rgp4-f9jj-fjwc
  3. 2026-10-25 EPSS moved to the below the 50th percentile

References

Exploit 1

  • TI-2024-03070 D-Link DNS-320L/DNS-325/DNS-327L/DNS-340L HTTP GET Request nas_sharing.cgi command injection KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-03069 D-Link DNS-320L/DNS-325/DNS-327L/DNS-340L HTTP GET Request nas_sharing.cgi hard-coded credentials KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-00708 D-Link DIR-859 HTTP POST Request hedwig.cgi path traversal KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-10693 OS Command injection vulnerability in D-Link DIR820LA1_FW105B03 allows attackers to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-17249 D-Link Go-RT-AC750 GORTAC750_revA_v101b03 and GO-RT-AC750_revB_FWv200b02 are vulnerable… KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09657 D-Link DIR-820L 1.05B03 was discovered to contain remote command execution (RCE)… KEVCVSS 3.1CRITICAL 9.8
See all 979 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences