Vulnerability in Koajs Cors
CVE-2023-49803
@koa/cors npm provides Cross-Origin Resource Sharing (CORS) for koa, a web framework for Node.js. Prior to version 5.0.0, the middleware operates in a way that if an allowed origin is not provided, it will return an `Access-Control-Allow-Origin` header with the value of the origin from the request. This behavior completely disables one of the most crucial elements of browsers - the Same Origin Policy (SOP), this could cause a very serious security threat to the users of this middleware. If such behavior is expected, for instance, when middleware is used exclusively for prototypes and not for production applications, it should be heavily emphasized in the documentation along with an indication of the risks associated with such behavior, as many users may not be aware of it. Version 5.0.0 fixes this vulnerability.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (18.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Koajs Cors — versions < 5.0.0
- Koajs Cross-Origin Resource Sharing For Koa
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2023-49803?
- CVE-2023-49803 is a high-severity vulnerability in Koajs Cors, classified under Origin Validation Error. CVSS score: 8.6/10. Published 2023-12-11.
- How severe is CVE-2023-49803?
- High severity. CVSS v3 base score is 8.6 out of 10.