PatchTheCVECVE-2026-18500: @fastify/jwt is a JSON Web Token plugin for Fastify
CVE-2026-18500 is a high-severity flaw (CVSS 8.1) affecting fastify\/jwt. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
@fastify/jwt is a JSON Web Token plugin for Fastify. In versions before 10.2.2, a per-request verification key passed to request.jwtVerify({ key }) is silently overridden by the plugin's globally configured secret, because the option merge applies the global key last. Applications that use different keys for different authorization domains, for example separate user and admin keys, therefore accept a token signed with the global key on a route th
Why this priority
- High severity
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.1 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 83%) |
| CISA exploited list | No |
| Weakness | CWE-347 |
| Published | 2026-08-15 |
| Last modified | 2026-09-04 |
Last updated 2026-09-04 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-18500?
fastify\/jwt: upgrade to 10.2.2. Exact commands for each OS are on this page.
Is CVE-2026-18500 being exploited?
CVE-2026-18500 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-18500 affect?
CVE-2026-18500 affects fastify\/jwt. Severity is high (CVSS 8.1). @fastify/jwt is a JSON Web Token plugin for Fastify. In versions before 10.2.2, a per-request verification key passed to request.jwtVerify({ key }) is silently overridden by the plugin's globally configured secret, because the option merge
How urgent is CVE-2026-18500?
Priority 33/100. High severity