CVE-2026-34563 is a critical stored cross-site scripting flaw in CI4MS, a CodeIgniter 4 based CMS. NVD scores it 9.1. Backup upload and metadata handling does not sanitize the backup file name, which is later rendered in several backup management views. Upgrade to ci4ms 0.31.0.0 or later.
What's affected
CI4MS (ci4-cms-erp ci4ms) versions before 0.31.0.0. The fixed release is 0.31.0.0.
Any site running an older build with the affected feature reachable to a signed in user is in scope.
How to check if you're exposed
Find the ci4ms version your site runs. If you deployed from a git checkout, git describe --tags in the project folder shows the nearest release tag. Otherwise look at the release or commit you installed from.
Anything older than 0.31.0.0 is in scope. The record names no workaround, so the version number is the test. The advisory linked under Sources lists the exact affected range.
What to do now
- Upgrade ci4ms to 0.31.0.0 or later and redeploy.
- Until you can, limit who holds accounts that can upload backups, and review those accounts.
- Look through existing backup records for entries that contain script tags or event handler attributes, and clean them.
- Sign out active sessions for administrators after the upgrade.
Why it matters
The weakness class is CWE-79, cross-site scripting. The record says a crafted SQL backup file can insert script content into the backup file name server side. That name is then shown in multiple backup management views without output encoding, which makes it a blind XSS.
Stored XSS is worse than the reflected kind because the script waits in the database and runs for every person who later opens the page. The CVSS vector has Scope Changed, which reflects that the script runs in the browser of someone else, often an administrator. The usual fix is output encoding on every place the stored value is rendered, plus input validation.
The record does not flag this CVE as listed in CISA's Known Exploited Vulnerabilities catalog, and the advisory I read does not say it is exploited.
Quick check
What should I review besides upgrading?
Check who has the permission to upload backups and look at existing backup entries for odd file names. Backups also hold your data, so treat that permission as sensitive.
Sources
Last reviewed: 19 October 2026.
