CVE-2021-40186Public exploitNetwork attack vector

Authenticated SSRF via unvalidated image URL redirects

Published May 31, 2022 · Updated Aug 4, 2024

SSRF in DNN Platform 9.0 through 9.10.2 allows remote authenticated users to read internal HTTP resources through avatar uploads. FileUploadController validates only the original image-looking URL, then HttpWebRequest follows redirects without validating the final destination and stores its response. A registered account and profile image uploads are required; reachable intranet services or cloud metadata can be disclosed through the saved file.

CVSS severity6.5
Medium
EPSS probability1.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

SSRF in DNN Platform 9.0 through 9.10.2 allows remote authenticated users to read internal HTTP resources through avatar uploads. FileUploadController validates only the original image-looking URL, then HttpWebRequest follows redirects without validating the final destination and stores its response. A registered account and profile image uploads are required; reachable intranet services or cloud metadata can be disclosed through the saved file.

The record

CVE
CVE-2021-40186
Published
May 31, 2022
Updated
Aug 4, 2024
Vendor
DNN Software
Product
DNN Platform
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 31, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=9.0 <9.11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

DNN Software · DNN Platformversion=9.0 <9.11.0

Published CVSS scores

6.5AppCheck Ltd.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo