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CVE-2026-48707— InstantCMS vulnerable to SSRF via upload redirect bypass allows internal network service scanning

Quick assessment

Affected
instantsoft icms2
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

InstantCMS 是一个免费且开源的内容管理系统。2.18.2 之前的版本在文件上传功能（位于 第 509-532 行）中存在服务端请求伪造（SSRF）漏洞。当“从 URL 上传”功能跟随 HTTP 重定向时，重定向的目标 URL 会绕过私有 IP 地址黑名单检查。这使得经过身份验证的用户能够扫描并访问内部网络服务。该漏洞已在 2.18.2 版本中修复。

CVSS 3.1 · Low EPSS 0.03% · P9

Possible ATT&CK Techniques 1 AI

T1019

Affected Version Matrix 1

VendorProduct Version RangeStatus
instantsoft icms2 < 2.18.2 affected
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I. Basic Information for CVE-2026-48707

Vulnerability Information
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Vulnerability Title
InstantCMS vulnerable to SSRF via upload redirect bypass allows internal network service scanning
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
服务端请求伪造(SSRF)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
instantsoft icms2 < 2.18.2 -

II. Public POCs for CVE-2026-48707

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III. Intelligence Information for CVE-2026-48707

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Patches & Fixes for CVE-2026-48707 (1)

Vendor Advisories for CVE-2026-48707 (1)

IV. Related Vulnerabilities

Same product: icms2
Same vendor: instantsoft
Same weakness: CWE-918

V. Comments for CVE-2026-48707

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