CVE-2023-40033Network attack vector

File disclosure and SSRF via spoofed avatar upload

Published Aug 16, 2023 · Updated Oct 2, 2024

SSRF and local file disclosure in Flarum before 1.8.0 allow remote authenticated users to access server-side resources via avatar uploads. Avatar validation and processing pass an uploaded stream to intervention/image, which interprets URL-shaped contents as a location and fetches them despite a spoofed image MIME type. A basic account with avatar-upload access is sufficient to trigger blind server requests, read local files, or use the response as an oracle.

CVSS severity7.1
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF and local file disclosure in Flarum before 1.8.0 allow remote authenticated users to access server-side resources via avatar uploads. Avatar validation and processing pass an uploaded stream to intervention/image, which interprets URL-shaped contents as a location and fetches them despite a spoofed image MIME type. A basic account with avatar-upload access is sufficient to trigger blind server requests, read local files, or use the response as an oracle.

The record

CVE
CVE-2023-40033
Published
Aug 16, 2023
Updated
Oct 2, 2024
Vendor
Flarum
Product
Flarum
Classifications
CWE-98, CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 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?

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

  1. Affected versionversion=< 1.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Flarum · Flarumversion=< 1.8.0

Published CVSS scores

7.1GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-98Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

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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