---
description: Cloudflare Managed Ruleset emergency release introducing rules for Brotli-encoded request bodies and the Next.js image optimization endpoint
title: WAF Release - 2026-10-25 - Emergency - Cloudflare Managed Ruleset
image: https://developers.cloudflare.com/changelog/post/2026-10-25-emergency-waf-release/og.png?v=0940de90a6b6929e
---

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October 25, 2026

## WAF Release - 2026-10-25 - Emergency - Cloudflare Managed Ruleset

[WAF](https://developers.cloudflare.com/waf/)

Copy as Markdown| [View as Markdown](https://developers.cloudflare.com/changelog/post/2026-10-25-emergency-waf-release/index.md)| [Agent setup](https://developers.cloudflare.com/agent-setup/)

This emergency release will add two rules related to the Brotli vulnerability **CVE-2026-111497** to the Cloudflare Managed Ruleset. Both rules will be **enabled by default** with their action set to **Log**, providing visibility into matching requests so customers can evaluate the impact before choosing to block them.

**Rule behavior**

- **Brotli rule:** Matches incoming requests that declare Brotli request-body encoding ( `Content-Encoding: br`), including legitimate clients submitting Brotli-encoded request bodies. It does not match `Accept-Encoding: br` or affect Cloudflare's Brotli response-compression settings. The rule's default action is **Log**.
- **Next.js rule:** Matches requests to the Next.js image optimization endpoint ( `/_next/image`), including legitimate image optimization traffic. The default action is **Log** and does not block requests. Changing the action to **Block** may prevent optimized images from loading and disrupt image delivery for applications using this endpoint.

**Default behavior**

- Both rules will log matching requests without blocking them when the ruleset defaults are used.
- Customers will be able to review matches in analytics and configure a blocking action for either rule if desired.
- Enabling these rules in **Log** mode provides visibility only; it does not block requests matching these rules.

**Important: Check existing action overrides**

If you have configured a ruleset-level action override that applies **Block** to these rules, matching requests may be blocked as soon as the rules are deployed, despite their default **Log** action. This may result in false positives and block legitimate traffic.

Review your existing ruleset overrides before deployment. If you want to evaluate these rules without blocking traffic, configure rule-specific overrides to use **Log** and review matching requests before switching to **Block**.

| Ruleset | Rule ID | Legacy Rule ID | Description | Previous Action | New Action | Comments |
| --- | --- | --- | --- | --- | --- | --- |
| Cloudflare Managed Ruleset | ...ca706f3c | N/A | Brotli - Request Content-Encoding - CVE:CVE-2026-111497 | N/A | Log | This is a new detection. |
| Cloudflare Managed Ruleset | ...402fe5bb | N/A | Next.js - Image Optimizer Path - CVE:CVE-2026-111497 | N/A | Log | This is a new detection. |

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