What’s Vulnerable › Vulnerabilities

CVE-2026-107275: @fastify/jwt vulnerable to missing token expiration when temporal options cannot be parsed

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-08 · updated 2026-10-08
• Weakness: CWE-390

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.

Affected products

• @fastify/jwt: before 10.2.3 — fixed in 10.2.3

How to fix

Upgrade to a fixed version: @fastify/jwt 10.2.3. Check the vendor advisory for mitigations.

References

• https://cna.openjsf.org/security-advisories.html
• https://github.com/fastify/fastify-jwt/security/advisories/GHSA-9x4w-r9p5-5h7m

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