CVE-2026-55872
GYM One admin user list is vulnerable to stored cross-site scripting
Description
GYM One is open-source gym management software for fitness centers, personal trainers, and sports clubs. Prior to 1.4.1, GYM One's admin/users/index.php renders the stored firstname, lastname, and email profile fields into the administrator user list without HTML output encoding. An attacker who can store values in those fields can cause content to execute in an administrator's browser when the administrator visits /admin/users/. The persistent script can access administrator-session data or perform actions with the administrator's privileges until the stored record is removed. This issue is fixed in version 1.4.1.
INFO
Published Date :
Oct. 15, 2026, 7:17 p.m.
Last Modified :
Oct. 15, 2026, 7:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-55872
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update GYM One to version 1.4.1.
- Sanitize all user-supplied input before storing.
- Encode output for all profile fields.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55872.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55872 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55872
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55872 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55872 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Oct. 15, 2026
Action Type Old Value New Value Added Description GYM One is open-source gym management software for fitness centers, personal trainers, and sports clubs. Prior to 1.4.1, GYM One's admin/users/index.php renders the stored firstname, lastname, and email profile fields into the administrator user list without HTML output encoding. An attacker who can store values in those fields can cause content to execute in an administrator's browser when the administrator visits /admin/users/. The persistent script can access administrator-session data or perform actions with the administrator's privileges until the stored record is removed. This issue is fixed in version 1.4.1. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/55xxx/CVE-2026-55872.json">CVE-2026-55872</a> Added Reference https://github.com/mayerbalintdev/GYM-One/commit/d3a0cf134f0ab3ac12aee7dca283b93c4290dcc4 Added Reference https://github.com/mayerbalintdev/GYM-One/releases/tag/V1.4.1 Added Reference https://github.com/mayerbalintdev/GYM-One/security/advisories/GHSA-75g9-vp9w-5388