XSS in Flextype
CVE-2026-89145
Flextype CMS versions 0.9.9 through 1.0.0-alpha.3 fail to HTML-escape plugin directory names in the dependency error page rendered by getValidPluginsDependencies(). Attackers with write access to the plugins directory can create a plugin with HTML characters in its name to execute arbitrary scripts in users' browsers when dependency validation fails.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (7.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 7.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/flextype/flextype/issues/597 (issue-tracking)
- github.com/flextype/flextype (product)
- github.com/flextype/flextype/blob/aea4ead8c449ea5517ed53b6dcbd28b0a528ad9d/src/… (technical-description)
- www.vulncheck.com/advisories/flextype-cms-0.9.9-through-1.0.0-alpha.3-stored-xs… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-89145?
- CVE-2026-89145 is a medium-severity vulnerability in Flextype, classified under Cross-site Scripting. CVSS score: 4.2/10. Published 2026-09-11.
- How severe is CVE-2026-89145?
- Medium severity. CVSS v3 base score is 4.2 out of 10.