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GHSA-hm8q-7f3q-5f36
No affected components available
Summary
Improper validation of the JWT NumericDate claims exp, nbf, and iat in hono/utils/jwt allows tokens with non-spec-compliant claim values to silently bypass time-based checks. This issue is not exploitable by an anonymous attacker; it only manifests when a malformed claim value reaches verify() — typically when the application itself issues such tokens, or when the signing key is otherwise under attacker control.
Details
The validation routine combined option, presence, and threshold checks in a single short-circuiting expression, so several classes of malformed values were silently skipped instead of rejected:
- A falsy numeric value short-circuited the presence check.
- A non-finite numeric value compared as never-after-now and never-expired.
- A non-numeric type produced NaN comparisons that evaluated false.
This deviates from RFC 7519 §4.1.4, which defines NumericDate as a finite JSON numeric value.
Impact
An actor able to issue tokens accepted by the application may craft tokens whose exp, nbf, or iat claims silently bypass time-based enforcement. This may lead to:
- Tokens treated as never expiring even with
expconfigured on the verifier. - Tokens with a future
nbfaccepted as currently valid. - Tokens with a future
iataccepted as legitimately issued.
Deployments using a well-formed token issuer and protecting the signing key are not affected.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs high-level or administrative privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.
Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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