CVE-2023-3804Public exploitNetwork attack vector

Webshell execution via unrestricted FileHandler upload

Published Jul 21, 2023 · Updated Aug 2, 2024

Unrestricted file upload in Chengdu Flash Flood Disaster Monitoring and Warning System 2.0 allows attackers to install a webshell. The FileHandler.ashx SaveFile and WriteFile path accepts an Action=Upload multipart userFile and attacker-chosen .aspx filename without filtering dangerous file types. The published request supplies no authentication header and stores the server-side page despite an error response, enabling code execution under the web service account.

CVSS severity9.8
Critical
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Chengdu Flash Flood Disaster Monitoring and Warning System 2.0 allows attackers to install a webshell. The FileHandler.ashx SaveFile and WriteFile path accepts an Action=Upload multipart userFile and attacker-chosen .aspx filename without filtering dangerous file types. The published request supplies no authentication header and stores the server-side page despite an error response, enabling code execution under the web service account.

The record

CVE
CVE-2023-3804
Published
Jul 21, 2023
Updated
Aug 2, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1505.003, T1105
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5VulDBCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
5.2VulDBAV:A/AC:L/Au:S/C:P/I:P/A:P

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

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1505.003Server Software Component: Web Shell
T1105Ingress Tool Transfer

Public exploit references

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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