CVE-2026-37503 — Cross-Site Scripting (XSS)
CVE-2026-37503 — Cross-Site Scripting (XSS) in V2Board thru 1.7.4. The custom_html field in theme configuration is rendered using Blade unescaped output in public/theme/v2board/dashboard.blade.php. An admin can inject arbitrary JavaScript via the saveThemeConfig API. All site visitors execute the pa
What This Means For You
- If your environment is affected by this vulnerability type, review your exposure and prioritize patching based on your environment. Monitor vendor advisories for CVE-2026-37503 updates and patches.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-37503 - V2Board admin injects XSS via theme config
title: CVE-2026-37503 - V2Board admin injects XSS via theme config
id: scw-2026-05-01-ai-1
status: experimental
level: critical
description: |
Detects an administrator attempting to inject JavaScript into the 'custom_html' field via the saveThemeConfig API endpoint in V2Board. This is the specific method described for exploiting CVE-2026-37503, allowing for XSS attacks against site visitors.
author: SCW Feed Engine (AI-generated)
date: 2026-05-01
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-37503/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/api/v1/theme/config/save'
cs-method:
- 'POST'
cs-uri-query|contains:
- 'custom_html'
selection_payload:
cs-uri-query|contains:
- '<script>'
condition: selection AND selection_payload
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-37503 | vulnerability | CVE-2026-37503 |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 01, 2026 at 19:16 UTC |
This content was curated and summarized by Shimi's Cyber World for informational purposes. It is not copied or republished in full. All intellectual property rights remain with the original author and source.
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