CVE-2021-27342 json
An authentication brute-force protection mechanism bypass in telnetd in D-Link Router model DIR-842 firmware version 3.0.2 allows a remote…
published 2021-05-17 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14102
- cvss
- 5.9
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 4.6%
- EPSS 4.6% chance of exploitation in 30 days, percentile 91%
- public exploits
- 0
- none known
Summary
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
Exploit prediction
4.56% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/guywhataguy/D-Link-CVE-2021-27342-exploit/blob/main/dlink-telnet-exploit-CVE-2021-27342.py referenced PoC, tagged "exploit" by a source, unverified
- blog.whtaguy.com https://blog.whtaguy.com/2021/05/d-link-router-cve-2021-27342.html referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Classification
- Weakness
-
- CWE-203 Observable Discrepancy
References
-
github.com
/guywhataguy/D-Link-CVE-2021-27342-exploit/blob/main/dlink-telnet-exploit-CVE-2021-27342.py
exploit, third-party-advisory
-
blog.whtaguy.com
/2021/05/d-link-router-cve-2021-27342.html
exploit, third-party-advisory
-
supportannouncement.us.dlink.com
/announcement/publication.aspx?name=SAP10225
vendor-advisory
Sources
- CVE List CVE-2021-27342
- NVD CVE-2021-27342
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.