CVE-2026-54290
hono: CORS Middleware reflects any Origin with credentials when `origin` defaults to the wildcard
Description
### Summary With `credentials: true` and no explicit `origin` (the default wildcard), the CORS Middleware reflects the request's `Origin` and sends `Access-Control-Allow-Credentials: true`. Any site can then make credentialed cross-origin requests and read the responses, exposing cookie-authenticated endpoints to arbitrary origins. ### Details The spec forbids `Access-Control-Allow-Origin: *` with credentials and browsers reject it, so this configuration used to fail closed. In affected versions the middleware reflects the request `Origin` instead, so it now succeeds for every origin, including `null`. The preflight also echoes the requested headers back, approving non-simple credentialed requests too. This issue arises when an application enables `credentials: true` and leaves `origin` unset or set to the wildcard. ### Impact Any third-party page a logged-in user visits can read the application's cookie-authenticated endpoints and perform credentialed state-changing requests. This affects applications that enable credentialed CORS without restricting `origin`.
How to fix CVE-2026-54290
To remediate CVE-2026-54290, upgrade the affected package to a fixed version below.
- —upgrade to 4.12.25 or later
Is CVE-2026-54290 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-54290.
Affected packages (1)
- from 0, < 4.12.25
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N |