CVE-2021-1201Network attack vector

Root code execution and reload via stack overflow

Published Jan 13, 2021 · Updated Nov 12, 2024

Stack-based buffer overflow in the web management interface of Cisco Small Business RV routers allows remote authenticated users to execute root code. The interface fails to validate data in crafted HTTP requests before processing it in a stack buffer; Cisco has not disclosed the affected handler or parameter. Valid administrator credentials and management-interface access are required, and successful exploitation executes code as root or reloads the device.

CVSS severity7.2
High
EPSS probability2.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in the web management interface of Cisco Small Business RV routers allows remote authenticated users to execute root code. The interface fails to validate data in crafted HTTP requests before processing it in a stack buffer; Cisco has not disclosed the affected handler or parameter. Valid administrator credentials and management-interface access are required, and successful exploitation executes code as root or reloads the device.

The record

CVE
CVE-2021-1201
Published
Jan 13, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Cisco Small Business RV Series Router Firmware
Classifications
CWE-121, T1068
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jan 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

ClamAV · Cisco Small Business RV Series Router Firmwareversion=n/a

Published CVSS scores

7.2Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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