dir-456u firmware vulnerabilities and fixes

Recent CVEs affecting dir-456u firmware, with upgrade or downgrade steps. 1 tracked.

Also searched as: dir 456u firmware, dir-456ufirmware.

dir-456u firmware has 1 tracked vulnerability, 1 critical. A fixed release or vendor patch exists for 0. Most recent: 2026-05-04. Highest priority: CVE-2026-42376 (score 54/100).

• CVE-2026-42376 CRITICAL 9.8 MITIGATE D-Link DIR-456U Hardware Revision A1 (End-of-Life, EOL) contains a hardcoded telnet backdoor

FAQ

How do I fix dir-456u firmware vulnerabilities?

Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.

Is dir-456u firmware being exploited right now?

None of the tracked dir-456u firmware CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.

Which dir-456u firmware CVE should I patch first?

CVE-2026-42376 currently ranks highest (54/100): D-Link DIR-456U Hardware Revision A1 (End-of-Life, EOL) contains a hardcoded telnet backdoor.

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