CVE-2026-37503

Description

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 payload, enabling cookie theft, session hijacking, or phishing.

CVSS v3.1 Score

6.9

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0003

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
v2board	v2board	< 1.7.4

References

Exploits

https://gist.github.com/sgInnora/1330e1a82caa79906eec55eeff2c99b9

Other References

https://github.com/v2board/v2board

Frequently Asked Questions

What is 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 payload, enabling cookie theft, session hijacking, or phishing. It has a CVSS v3.1 base score of 6.9 (MEDIUM).

How severe is CVE-2026-37503? +

CVE-2026-37503 has a CVSS v3.1 score of 6.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0003, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-37503? +

CVE-2026-37503 affects products from v2board, specifically: v2board. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-37503? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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