DD-WRT Stack-Based Buffer Overflow Vulnerability

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• NewsExploited · CISA KEVDD-WRT · DD-WRT

  DD-WRT Stack-Based Buffer Overflow Vulnerability

  CVE-2021-27137

  DD-WRT contains a stack-based buffer overflow vulnerability that could allow an unauthenticated attacker to overflow an internal buffer used by UPnP and trigger a code execution vulnerability.

  CISA's required action · due 24 Jul 2026 for U.S. federal civilian agencies

  Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

  Cited by CISA: svn.dd-wrt.com · nvd.nist.gov

  Added to KEV 21 Jul 2026 · Source checked 4 Nov 2026, 16:30 UTC · CISA KEV entry

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