CVE-2021-1473Known exploitationPublic exploitNetwork attack vector

Unauthenticated command execution via sessionid cookie injection

Published Apr 8, 2021 · Updated Nov 8, 2024

Command injection in the web interface of Cisco RV340-series routers before 1.0.03.21 allows remote attackers to execute OS commands. The upload.cgi handler inserts the sessionid cookie into a curl command with sprintf and passes the resulting string directly to popen without validation. The interface is reachable from the LAN by default and from the WAN only when remote management is enabled; injected commands run as www-data.

CVSS severity7.3
High
EPSS probability64.16%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in the web interface of Cisco RV340-series routers before 1.0.03.21 allows remote attackers to execute OS commands. The upload.cgi handler inserts the sessionid cookie into a curl command with sprintf and passes the resulting string directly to popen without validation. The interface is reachable from the LAN by default and from the WAN only when remote management is enabled; injected commands run as www-data.

The record

CVE
CVE-2021-1473
Published
Apr 8, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Small Business RV Series Router Firmware
Classifications
CWE-119, T1190, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 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 privilegesunauthenticated

What is affected?

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

Published CVSS scores

7.3CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1190Exploit Public-Facing Application
T1059.004Unix Shell

Public exploit references

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

Reported exploitation

Technologies

Your stack

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Your stack

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