What’s Vulnerable › Vulnerabilities

CVE-2021-27342

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-05-17 · updated 2026-06-17
• Weakness: CWE-203

Description

An authentication brute-force protection mechanism bypass in telnetd in D-Link Router model DIR-842 firmware version 3.0.2 allows a remote attacker to circumvent the anti-brute-force cool-down delay period via a timing-based side-channel attack

Affected products

• Dlink Dir-842E Firmware: through 3.0.2

References

• https://blog.whtaguy.com/2021/05/d-link-router-cve-2021-27342.html
• https://github.com/guywhataguy/D-Link-CVE-2021-27342-exploit/blob/main/dlink-telnet-exploit-CVE-2021-27342.py
• https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10225
• https://blog.whtaguy.com/2021/05/d-link-router-cve-2021-27342.html
• https://github.com/guywhataguy/D-Link-CVE-2021-27342-exploit/blob/main/dlink-telnet-exploit-CVE-2021-27342.py
• https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10225

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