CVE-2026-107275: @fastify/jwt

Vulnerability summary

CVE-2026-107275 is a medium (CVSS 6.8) vulnerability in @fastify/jwt. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.7% of scored vulnerabilities.

Timeline

1. 08-10-2026
   PublishedVulnerability first disclosed.
2. 08-10-2026
   Last modifiedVulnerability information updated.

Description

@fastify/jwt is a JSON Web Token plugin for the Fastify web framework. In versions before 10.2.3, a time span passed to expiresIn, notBefore, or maxAge that the plugin's parser cannot read, such as a compound span, a month unit, an ISO 8601 duration, a decimal comma, or a value with surrounding whitespace, is silently dropped instead of refused. On the signing path this produces a token with no expiration claim that never expires, and on the verification path a configured maxAge stops being enforced, so a token that should be rejected for age is accepted. The issue is fixed in @fastify/jwt 10.2.3, and users should upgrade to 10.2.3 or later. As a workaround, pass these options as a number of seconds, or verify that any time-span string parses to a finite value before relying on it.

• CWE-390Detection of Error Condition Without ActionThe product detects a specific error, but takes no actions to handle the error.
• CWE-613Insufficient Session ExpirationAccording to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."
• CWE-754Improper Check for Unusual or Exceptional ConditionsThe product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.