XSS in Storybookjs Telejson
CVE-2026-47099
TeleJSON prior to 6.0.0 contains a DOM-based cross-site scripting vulnerability in the parse() function that allows attackers to execute arbitrary JavaScript by delivering a crafted JSON payload containing a malicious _constructor-name_ property value. The custom reviver passes the constructor name directly to new Function() without sanitization when recreating object prototypes, enabling attackers to inject arbitrary JavaScript through vectors such as postMessage in cross-frame communication contexts to achieve script execution within the application.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (29.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
- Storybookjs Telejson — versions 0
Weakness classification (CWE)
References
- github.com/storybookjs/telejson/security/advisories/GHSA-ccgf-5rwj-j3hv (vendor-advisory, patch)
- www.vulncheck.com/advisories/telejson-dom-based-xss-via-parse-function (third-party-advisory)
- github.com/Niccolo10/Security-Advisories/blob/main/CVE-2026-47099/cve-2026-4709… (technical-description)
Frequently asked questions
- What is CVE-2026-47099?
- CVE-2026-47099 is a medium-severity vulnerability in Storybookjs Telejson, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-20.
- How severe is CVE-2026-47099?
- Medium severity. CVSS v3 base score is 6.1 out of 10.