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Not in CISA KEV
LOW severity

GHSA-hm8q-7f3q-5f36 — hono

LOW

GHSA-hm8q-7f3q-5f36 is a low-severity (CVSS 3.8) CWE-1284 vulnerability in hono. A fix is available for hono — see the affected versions and patch details below.

Hono has improper validation of NumericDate claims (exp, nbf, iat) in JWT verify()

Also known asCVE-2026-44459
Published
May 9, 2026
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-hm8q-7f3q-5f36.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs18th percentile — riskier than 18% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-hm8q-7f3q-5f36 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

6Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream
hononpm
46.1Mdownloads / week

Description

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 exp configured on the verifier.
  • Tokens with a future nbf accepted as currently valid.
  • Tokens with a future iat accepted as legitimately issued.

Deployments using a well-formed token issuer and protecting the signing key are not affected.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmhonoall versions4.12.18npm install hono@4.12.18

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update hono to 4.12.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hm8q-7f3q-5f36 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-hm8q-7f3q-5f36 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-hm8q-7f3q-5f36. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 val
O3 Security · Impact-Aware SCA

Is GHSA-hm8q-7f3q-5f36 in your dependencies?

O3 Security finds GHSA-hm8q-7f3q-5f36 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-hm8q-7f3q-5f36: hono (Low 3.8) | O3 Security