CVE-2023-4878Network attack vector

Internal resource access via unchecked upload URLs

Published Sep 10, 2023 · Updated Sep 26, 2024

SSRF in the upload-by-link feature of InstantCMS 2 before 2.16.1-git allows remote authenticated users to access internal HTTP resources. The cmsUploader::uploadFromLink method follows a hostname URL with cURL without rejecting names that resolve to private or reserved IPv4 addresses. An account permitted to upload a file by URL can make the server request internal services and receive returned content through the upload workflow.

CVSS severity5.4
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in the upload-by-link feature of InstantCMS 2 before 2.16.1-git allows remote authenticated users to access internal HTTP resources. The cmsUploader::uploadFromLink method follows a hostname URL with cURL without rejecting names that resolve to private or reserved IPv4 addresses. An account permitted to upload a file by URL can make the server request internal services and receive returned content through the upload workflow.

The record

CVE
CVE-2023-4878
Published
Sep 10, 2023
Updated
Sep 26, 2024
Vendor
InstantCMS Team
Product
InstantCMS 2
Classifications
CWE-918, T1046
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 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-git

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

InstantCMS Team · InstantCMS 2version=unspecified <2.16.1-git

Published CVSS scores

4.3huntr.devCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.4NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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.

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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-918Server-Side Request Forgery (SSRF)
T1046Network Service Discovery

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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