CVE-2026-55872
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/.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.29%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.7 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- EPSS
- 0.29% probability · 21th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Source
- security-advisories@github.com
EPSS moved from 0.2% on 16 October 2026 to 0.3% on 26 October 2026.
References
- https://github.com/mayerbalintdev/GYM-One/commit/d3a0cf134f0ab3ac12aee7dca283b93c4290dcc4
- https://github.com/mayerbalintdev/GYM-One/releases/tag/V1.4.1
- https://github.com/mayerbalintdev/GYM-One/security/advisories/GHSA-75g9-vp9w-5388
- https://github.com/mayerbalintdev/GYM-One/security/advisories/GHSA-75g9-vp9w-5388
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.