Server-Side Request Forgery Vulnerability in OctoberCMS by October
CVE-2026-100909

6.9MEDIUM

Key Information:

Vendor

October

Status
Octobercms
Vendor
CVE Published:
28 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-100909?

A vulnerability exists in OctoberCMS prior to version 4.3.5 that allows for server-side request forgery through the manipulation of the getSourcePathForResize function in the ResizeImages.php component. An attacker can exploit this vulnerability remotely, potentially leading to unauthorized access or data exposure. It is crucial to upgrade to version 4.3.5 or 4.4.0, which contain a patch to eliminate this issue. The relevant patch is identified as 0e9736aa2c6d6bd3d60ff6ef9e0b4d32ce387f58.

Affected Version(s)

OctoberCMS 4.1.0

OctoberCMS 4.1.1

OctoberCMS 4.1.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-100909 - Proof of Concept

References

https://vuldb.com/vuln/410869
vdb-entrytechnical-description
https://vuldb.com/vuln/410869/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-100909
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

chenhuanlin (VulDB User)
.