CVE-2026-37503Public exploitNetwork attack vector

Stored XSS via unescaped theme configuration

Published May 1, 2026 · Updated May 1, 2026

Stored cross-site scripting in V2Board 1.7.4 and earlier allows remote authenticated users to run JavaScript in visitors' browsers. The dashboard Blade template inserts the saved custom_html value with unescaped output and no sanitization, so stored markup becomes executable page content. Administrative theme-configuration access is required to plant the payload; each visitor who loads the page then executes it, exposing sessions to theft or hijacking.

CVSS severity6.9
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in V2Board 1.7.4 and earlier allows remote authenticated users to run JavaScript in visitors' browsers. The dashboard Blade template inserts the saved custom_html value with unescaped output and no sanitization, so stored markup becomes executable page content. Administrative theme-configuration access is required to plant the payload; each visitor who loads the page then executes it, exposing sessions to theft or hijacking.

The record

CVE
CVE-2026-37503
Published
May 1, 2026
Updated
May 1, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, CAPEC-592, T1539
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.8NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
6.9MITRECVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
T1539Steal Web Session Cookie

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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