CVE-2026-3833 — Gnutls Information Disclosure

title: CVE-2026-3833 Gnutls nameConstraints Policy Bypass
id: scw-2026-04-30-ai-1
status: experimental
level: medium
description: |
  Detects potential exploitation of CVE-2026-3833 by looking for web requests that contain parameters indicative of a Gnutls nameConstraints policy bypass attempt. Attackers may craft requests to test or exploit this vulnerability where case-sensitive comparisons of 'dNSName' or 'rfc822Name' within 'excludedSubtrees' or 'permittedSubtrees' are bypassed, leading to policy violations.
author: SCW Feed Engine (AI-generated)
date: 2026-04-30
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-3833/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri-query|contains:
          - 'nameConstraints'
      cs-uri-query|contains:
          - 'dNSName'
      cs-uri-query|contains:
          - 'excludedSubtrees'
      cs-uri-query|contains:
          - 'permittedSubtrees'
      condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse