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HIGH

CVE-2026-55872

GYM One admin user list is vulnerable to stored cross-site scripting

CVSS v3

8.7

HIGH

EPSS Score

0.2 %

exploit probability, as of 2026-10-16

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-55872 yet.

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Published
2026-10-15
Last Modified
2026-10-15

Frequently asked questions

What is CVE-2026-55872?

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.

Is CVE-2026-55872 actively exploited?

Active exploitation of CVE-2026-55872 has not been confirmed. Its EPSS score was 0.2% on 2026-10-16, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-55872?

CVE-2026-55872 has a CVSS v3 base score of 8.7 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.

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