CVE-2023-49803@koa/cors has overly permissive origin policy
- 8.6HighCVSS base score
- 0.28%Exploitation in 30 daysEPSS · top 79% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
@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.
Timeline
ID reserved
By GitHub_M
- 11 days later
· 11 days later
Published
- 8 months later
· 8 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.28% · top 79% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npm@koa/corsGHSA-qxrj-hx23-xp82 (opens in a new tab)
References
References2
- https://github.com/koajs/cors/security/advisories/GHSA-qxrj-hx23-xp82 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/koajs/cors/commit/f31dac99f5355c41e7d4dd3c4a80c5f154941a11 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-3277 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-qxrj-hx23-xp82 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-49803)Record last updated .