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PatchSiren cyber security CVE debrief

CVE-2021-40655 D-Link CVE debrief

CVE-2021-40655 is an information disclosure vulnerability associated with the D-Link DIR-605 router family. CISA added it to the Known Exploited Vulnerabilities catalog on 2024-05-16, and CISA’s guidance says the affected hardware revisions are end-of-life or end-of-service and should be retired and replaced. For organizations that still have DIR-605 devices in service, this is a priority asset-removal and exposure-reduction issue rather than a routine patch-and-continue item.

Vendor
D-Link
Product
DIR-605 Router
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2024-05-16
Original CVE updated
2024-05-16
Advisory published
2024-05-16
Advisory updated
2024-05-16

Who should care

Security teams, network administrators, and asset owners who still have D-Link DIR-605 routers in inventory or deployed on internal or external networks should treat this as urgent. It is especially important for teams responsible for legacy network gear, branch offices, small offices, and any environment where end-of-life devices may have been left in place.

Technical summary

The available official records identify CVE-2021-40655 as an information disclosure issue affecting the D-Link DIR-605 router. The CISA KEV entry does not provide additional technical detail in the supplied corpus, but it does mark the vulnerability as known exploited and notes that the affected hardware revisions have reached EOL/EOS. The recommended remediation path in the official guidance is retirement and replacement of the affected devices.

Defensive priority

High for any environment with a DIR-605 still deployed. Because the product is EOL/EOS and the vulnerability is in CISA’s KEV catalog, the practical response is to prioritize removal from service over attempting to keep the device operational.

Recommended defensive actions

  • Inventory your network for any D-Link DIR-605 routers or related hardware revisions.
  • If found, treat the device as a high-priority legacy asset and plan retirement/replacement.
  • Follow vendor and CISA guidance to remove EOL/EOS hardware from service.
  • Reduce exposure immediately by ensuring the device is not unnecessarily reachable from untrusted networks.
  • Document the affected assets and verify they are absent from future procurement and deployment plans.

Evidence notes

The supplied source corpus includes CISA KEV metadata stating that this vulnerability affects legacy D-Link products and that all associated hardware revisions have reached EOL/EOS and should be retired and replaced per vendor instructions. The corpus also includes official CVE/NVD links, but no additional technical exploit details or CVSS score.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-40655 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-40655

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-40655 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-40655

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.