CVE-2026-110024

MEDIUM 6.8

Published 2026-10-18 · Last modified 2026-10-20

@fastify/jwt is a JWT utility plugin for Fastify. In versions prior to 10.2.5, the top-level sign and verify methods replace the globally configured defaults with the per-call options instead of merging them, so passing any per-call option silently drops every global default that the call does not restate, including temporal protections such as token expiration and maximum accepted token age. A token signed this way carries no expiration claim and never expires, and verification stops enforcing a configured maximum age, so stale or never-expiring tokens are accepted. The route-level decorators for signing and verifying already merge options and are not affected. The issue is fixed in @fastify/jwt 10.2.5, and users should upgrade to 10.2.5 or later.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 8th percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

6.8CVSS 3.1 · MEDIUM

ConfidentialityHigh
IntegrityHigh
AvailabilityNone

What an attacker needs

✓Access: Reachable over the network — no local access needed
⚠Privileges: Requires a low-privilege account
✓User interaction: No user interaction needed
⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

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Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot: 2026-10-26T13:52:32.101Z