Full Report
Use of Weak Credentials vulnerability (CVE-2026-4377) has been found in DWR-X1820 router.
Analysis Summary
# Vulnerability: Weak Default Password Generation in D-Link DWR-X1820
## CVE Details
- **CVE ID:** CVE-2026-4377
- **CVSS Score:** Not explicitly listed in the source (Estimated High based on impact)
- **CWE:** CWE-1391 (Use of Weak Credentials)
## Affected Systems
- **Products:** D-Link DWR-X1820 Router
- **Versions:** From 1.00B14CP to 1.00B16CP
- **Configurations:** Devices operating with default factory settings/credentials.
## Vulnerability Description
The D-Link DWR-X1820 router utilizes a predictable algorithm to generate its default administrative password. Specifically, the password is derived from the device's International Mobile Equipment Identity (IMEI) number. Furthermore, the device firmware does not mandate a password change upon initial setup.
The security flaw lies in the deterministic nature of the password generation; any actor who understands the derivation logic and obtains the device's IMEI can compute the administrative password.
## Exploitation
- **Status:** Reported (Coordinated Vulnerability Disclosure)
- **Complexity:** Low (Algorithm is predictable)
- **Attack Vector:** Local/Adjacent (IMEI acquisition often requires physical access to labels or proximity to the broadcasted cellular signal info, though remote acquisition may be possible depending on management interface exposure).
## Impact
- **Confidentiality:** High (Full access to router configuration and logs)
- **Integrity:** High (Ability to modify DNS settings, firewall rules, and firmware)
- **Availability:** High (Ability to disable the device or disrupt internet connectivity)
## Remediation
### Patches
- **Version 1.00B16CP:** D-Link has released a fix in this version to address the credential generation logic. Users should update to the latest firmware immediately.
### Workarounds
- **Manual Password Change:** Users should immediately change the default administrator password to a strong, unique, and randomly generated password.
- **Restrict Access:** Ensure the web management interface is not accessible from the Wide Area Network (WAN).
## Detection
- **Indicators of Compromise:** Unauthorized configuration changes, unknown connected devices in the ARP table, or logs indicating administrative logins from unexpected IP addresses.
- **Detection Methods:** Security audits should check if the administrative password matches the known derivation pattern based on the device IMEI.
## References
- **Vendor Advisory:** hxxps[://]www[.]dlink[.]com/en/security-advisory/
- **CERT Polska Advisory:** hxxps[://]cert[.]pl/en/posts/2026/05/vulnerability-in-dlink-dwr-x1820/
- **CVE Record:** hxxps[://]www[.]cve[.]org/CVERecord?id=CVE-2026-4377