CVE-2021-27137—DD-WRT Stack-Based Buffer Overflow Vulnerability
PUBLISHEDvulnerability record
2026-07-21 · last modified July 21, 2026
Metadata
Vulnerability Name
DD-WRT Stack-Based Buffer Overflow Vulnerability
Description
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.
Known To Be Used in Ransomware Campaigns?
Action
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.