CVE-2026-103540 (CVSS 6.3)

Description

A security vulnerability has been detected in formtools.org Form Tools up to 3.1.1. This vulnerability affects the function Clients::updateClientSettingsTab of the file global/code/Clients.class.php of the component Client Settings. The manipulation of the argument page_titles leads to improper neutralization of special elements used in a template engine. It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used. The project was informed of the problem early through an issue report but has not responded yet.

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CVSS v3.1 Score

6.3

MEDIUM

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

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.13%

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-791 CWE-791

CWE-1336 CWE-1336

References

Other References

https://github.com/formtools/core/issues/956 https://github.com/wawyw/cve_report/blob/main/formtools_1.md https://vuldb.com/cve/CVE-2026-103540 https://vuldb.com/submit/957845 https://vuldb.com/vuln/412350 https://vuldb.com/vuln/412350/cti

Frequently Asked Questions

What is CVE-2026-103540? +

A security vulnerability has been detected in formtools.org Form Tools up to 3.1.1. This vulnerability affects the function Clients::updateClientSettingsTab of the file global/code/Clients.class.php of the component Client Settings. The manipulation of the argument page_titles leads to improper neutralization of special elements used in a template engine. It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used. The project was informed of the problem early through an issue report but has not responded yet. It has a CVSS v3.1 base score of 6.3 (MEDIUM).

How severe is CVE-2026-103540? +

CVE-2026-103540 has a CVSS v3.1 score of 6.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-103540? +

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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