Coverage › CVE-2021-27137

CVE-2021-27137 Unmapped

DD-WRT Stack-Based Buffer Overflow Vulnerability

Vendor / product

DD-WRT — DD-WRT

Description (CISA)

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.

Added to KEV

2026-07-21 — after the latest CTID mapping snapshot (2025-07-28)

Due date

2026-07-24

Required 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.

Known ransomware use

Unknown

CWE

CWE-121

CISA notes

This vulnerability affects a common open-source component, third-party library, proprietary implementation, or a protocol used by different products. Please check with specific vendors for information on patching status. For more information, please see: https://svn.dd-wrt.com/changeset/45724
BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
https://nvd.nist.gov/vuln/detail/CVE-2021-27137

Elsewhere

cve.org · NVD · CISA KEV · JSON

ATT&CK techniques