What is the CVSS score of CVE-2021-47854?

CVE-2021-47854 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Which versions of DD-WRT are affected by CVE-2021-47854?

Organizations using DD-WRT version 45723 face critical risk from CVE-2021-47854, a buffer overflow vulnerability rated CVSS 9.8.

Is there a public PoC exploit available for CVE-2021-47854?

Yes, a public proof-of-concept exploit is available for CVE-2021-47854. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2021-47854?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.

DD-WRT CVE-2021-47854

CRITICAL

Classic Buffer Overflow (CWE-120)

2026-01-21 disclosure@vulncheck.com

Buffer Overflow

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Jan 26, 2026 - 15:04 vuln.today

Public exploit code

CVE Published

Jan 21, 2026 - 18:16 nvd

CRITICAL 9.8

DescriptionCVE.org

DD-WRT version 45723 contains a buffer overflow vulnerability in the UPNP network discovery service that allows remote attackers to potentially execute arbitrary code. Attackers can send crafted M-SEARCH packets with oversized UUID payloads to trigger buffer overflow conditions on the target device.

AnalysisAI

DD-WRT firmware version 45723 has a buffer overflow in the UPnP network discovery service allowing remote attackers to execute code on the router without authentication.

Technical ContextAI

DD-WRT v45723 has a CWE-120 classic buffer overflow in its UPnP service handler. Since UPnP typically listens on the LAN interface without authentication, any device on the network can trigger the overflow.

Affected ProductsAI

DD-WRT firmware v45723

RemediationAI

Update DD-WRT firmware. Disable UPnP if not required.

CVE-2021-47854 vulnerability details – vuln.today

Back

DD-WRT CVE-2021-47854

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

Affected ProductsAI

RemediationAI

Share

External POC / Exploit Code