CVE-2021-1472Known exploitationPublic exploitNetwork attack vector

Unauthenticated file upload via faulty session check

Published Apr 8, 2021 · Updated Nov 8, 2024

Authentication bypass in Cisco Small Business RV Series router firmware allows remote attackers to upload files via crafted HTTP requests. Technical analysis of RV34X firmware shows that nginx upload rules accept any non-null Authorization header instead of validating credentials or matching a session cookie. No account or user interaction is required; uploaded files reach restricted temporary directories and are expected to be deleted.

CVSS severity5.3
Medium
EPSS probability71.83%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Cisco Small Business RV Series router firmware allows remote attackers to upload files via crafted HTTP requests. Technical analysis of RV34X firmware shows that nginx upload rules accept any non-null Authorization header instead of validating credentials or matching a session cookie. No account or user interaction is required; uploaded files reach restricted temporary directories and are expected to be deleted.

The record

CVE
CVE-2021-1472
Published
Apr 8, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Small Business RV Series Router Firmware
Classifications
CWE-287, CWE-119, T1190
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

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
5.3CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-287Improper Authentication
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1190Exploit Public-Facing Application

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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