CVE-2026-48707
InstantCMS vulnerable to SSRF via upload redirect bypass allows internal network service scanning
Description
InstantCMS is a free and open source content management system. Versions prior to 2.18.2 have a Server-Side Request Forgery (SSRF) vulnerability in the file upload functionality (`system/core/uploader.php` at lines 509-532). When the "upload from URL" feature follows an HTTP redirect, the redirected target URL bypasses the private IP address blacklist check. This allows authenticated users to scan and access internal network services. Version 2.18.2 contains a fix.
INFO
Published Date :
Sept. 8, 2026, 6:17 p.m.
Last Modified :
Sept. 11, 2026, 9:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update InstantCMS to version 2.18.2.
- Apply vendor patch for uploaded functionality.
- Review file upload configurations.
- Monitor network access logs.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-48707.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-48707 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-48707
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-48707 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-48707 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 11, 2026
Action Type Old Value New Value Added Reference https://github.com/instantsoft/icms2/security/advisories/GHSA-cm47-mwv3-f534 Added SSVC {'id': 'CVE-2026-48707', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-11T20:50:45.764807Z'} -
New CVE Received by [email protected]
Sep. 08, 2026
Action Type Old Value New Value Added Description InstantCMS is a free and open source content management system. Versions prior to 2.18.2 have a Server-Side Request Forgery (SSRF) vulnerability in the file upload functionality (`system/core/uploader.php` at lines 509-532). When the "upload from URL" feature follows an HTTP redirect, the redirected target URL bypasses the private IP address blacklist check. This allows authenticated users to scan and access internal network services. Version 2.18.2 contains a fix. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-918 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/48xxx/CVE-2026-48707.json">CVE-2026-48707</a> Added Reference https://github.com/instantsoft/icms2/commit/04b8fe0eb75fc5f44eecb15684c7d3660586683d Added Reference https://github.com/instantsoft/icms2/security/advisories/GHSA-cm47-mwv3-f534