CVE-2026-32738 — Denial of Service

title: Potential libheif DoS Exploit Attempt (CVE-2026-32738)
id: scw-2026-05-19-ai-1
status: experimental
level: high
description: |
  Detects attempts to exploit CVE-2026-32738 by serving a crafted HEIF file. The vulnerability occurs when a HEIF file with 'samples_per_chunk=0' in the stsc box is processed, leading to a denial of service. This rule looks for requests containing '.heif' file extensions and the specific parameter 'samples_per_chunk=0' in the query string, indicating a potential exploit attempt.
author: SCW Feed Engine (AI-generated)
date: 2026-05-19
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-32738/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri|contains:
          - '.heif'
      cs-uri-query|contains:
          - 'samples_per_chunk=0'
      condition: cs-uri AND cs-uri-query
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse