Admin session theft via unescaped blacklist note
Published Apr 8, 2026 · Updated Apr 8, 2026
Stored XSS in CI4MS before 0.31.4.0 allows remote authenticated users to execute JavaScript in another administrator's browser. UserController::ajax_blackList_post() stores the note with only required-field validation, and users() inserts it unescaped into data-note HTML. An administrator with blacklist privileges must store the note, and a second administrator must load the user list; the payload can steal that viewer's session cookie.
Summary
What happened
Stored XSS in CI4MS before 0.31.4.0 allows remote authenticated users to execute JavaScript in another administrator's browser. UserController::ajax_blackList_post() stores the note with only required-field validation, and users() inserts it unescaped into data-note HTML. An administrator with blacklist privileges must store the note, and a second administrator must load the user list; the payload can steal that viewer's session cookie.
The record
- CVE
- CVE-2026-39391
- Published
- Apr 8, 2026
- Updated
- Apr 8, 2026
- Vendor
- Ci4MS
- Product
- CI4MS
- Classifications
- CWE-79, T1539
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Apr 8, 2026CVE publishedPublication date reported by the CVE source.
- Apr 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.31.4.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-7cm9-v848-cfh2 authenticated stored-XSS proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo