CVE-2023-4651Public exploitNetwork attack vector

Authenticated SSRF via image upload links

Published Aug 31, 2023 · Updated Oct 1, 2024

SSRF in InstantCMS 2 before 2.16.1 allows remote authenticated users to make server-side requests through image uploads. The uploadFromLink method passes the posted link directly to cURL; the patch adds URL validation, rejects literal IPv4 hosts, and restricts protocols to HTTP and HTTPS. A valid account and an image field with link uploads enabled are required, and successful exploitation reaches resources visible from the web server.

CVSS severity6.4
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in InstantCMS 2 before 2.16.1 allows remote authenticated users to make server-side requests through image uploads. The uploadFromLink method passes the posted link directly to cURL; the patch adds URL validation, rejects literal IPv4 hosts, and restricts protocols to HTTP and HTTPS. A valid account and an image field with link uploads enabled are required, and successful exploitation reaches resources visible from the web server.

The record

CVE
CVE-2023-4651
Published
Aug 31, 2023
Updated
Oct 1, 2024
Vendor
InstantCMS Team
Product
InstantCMS 2
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 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=unspecified <2.16.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

InstantCMS Team · InstantCMS 2version=unspecified <2.16.1

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
6.4Huntr CNACVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/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.

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 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

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Your stack

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