CVE-2026-33857 — Apache HTTP Server: Out-of-Bounds $1

title: CVE-2026-33857 - Apache HTTP Server mod_proxy_ajp Out-of-Bounds Read Attempt
id: scw-2026-05-04-ai-1
status: experimental
level: high
description: |
  This rule detects attempts to exploit CVE-2026-33857 in Apache HTTP Server. The vulnerability lies in mod_proxy_ajp and can be triggered by specific requests that lead to an out-of-bounds read. This detection looks for requests containing '/ajp13://' in the URI, typically indicative of an attempt to interact with the AJP protocol, combined with a GET method and a 500 Internal Server Error status, which can be a symptom of such an exploit.
author: SCW Feed Engine (AI-generated)
date: 2026-05-04
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-33857/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri|contains:
          - '/ajp13://'
      cs-method:
          - 'GET'
      sc-status:
          - '500'
      condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse