Cross-site scripting in October CMS - #VU149490
Published: September 14, 2026
Vulnerability identifier: #VU149490
CSH Severity: Low
CVSS v4: 2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]
CVE-ID: N/A
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary script in the backend origin.
The vulnerability exists due to improper neutralization of input during web page generation in the backend Event Log preview\'s client-side exception beautifier when an administrator opens a log preview containing crafted brace tokens in an exception message. A remote privileged user can supply a logged exception message containing crafted brace tokens to execute arbitrary script in the backend origin.
The crafted payload remains persistent until the affected log entry is deleted.
Affected software
October CMS
Remediation
Install security update from vendor's website.
October CMS - addressed in versions 3.7.17, 4.2.23