SharePoint RCE and Rails Active Storage RCE now blocked by WAF

This release introduces new rules and updates Microsoft SharePoint RCE alongside enhanced SSRF cloud protection rule actions.

Key Findings

• CVE-2026-50522: An insecure deserialization vulnerability in Microsoft SharePoint Server. This may allow an unauthenticated attacker to execute arbitrary code using crafted requests.
• CVE-2026-66066: An improper input processing vulnerability in Ruby on Rails Active Storage image variant transformations. This may allow an unauthenticated attacker to perform arbitrary file reads and achieve Remote Code Execution (RCE) using maliciously crafted payload requests.
• Generic Cloud Protections: Added improved detection logic targeting Server-Side Request Forgery (SSRF) in cloud-hosted applications.

Ruleset

Rule ID

Legacy Rule ID

Description

Previous Action

New Action

Comments

Cloudflare Managed Ruleset

...052b07cf

N/A

Microsoft SharePoint - Remote Code Execution - CVE:CVE-2026-50522

Log

Block

This is a new detection.

Cloudflare Managed Ruleset

...3a5b40d6

N/A

Rails - Arbitrary File Read & RCE - CVE:CVE-2026-66066

Block

Block

This was labeled as File Upload - RCE.

Cloudflare Managed Ruleset

...8242627b

N/A

SSRF - Local

Disabled

-

This detection has been removed.

Cloudflare Managed Ruleset

...743a63ec

N/A

SSRF - Local - 2 - Beta

Disabled

-

This detection has been removed.

Cloudflare Managed Ruleset

...c2e84e2d

N/A

SSRF - Cloud - Beta

Disabled

-

This detection has been removed.

Cloudflare Managed Ruleset

...ab8af26f

N/A

SSRF - Cloud - 2 - Beta

Disabled

-

This detection has been removed.

Cloudflare Managed Ruleset

...25ba9d7c

N/A

SSRF - Cloud

Disabled

Block

We are changing the action for this rule from Disabled to BLOCK

Cloudflare Managed Ruleset

...01a076eb

N/A

SSRF - Local - Beta

Disabled

-

This detection has been removed.