CVE-2026-54290 — hono
HIGHCVE-2026-54290 is a high-severity (CVSS 7.1) CWE-942 vulnerability in hono. A fix is available for hono — see the affected versions and patch details below.
Hono: CORS Middleware reflects any Origin with credentials when `origin` defaults to the wildcard
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-54290.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
hononpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hono | all versions | 4.12.25npm install hono@4.12.25 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hono to 4.12.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54290 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-54290 in your dependencies?
Find it across npm, including transitive dependencies.