# CVE-2026-44459: Hono: Improper validation of NumericDate claims (exp, nbf, iat) in JWT verify()

> Improper validation of JWT time claims allows bypassing expiration checks if malformed tokens are issued or keys are compromised.

- **Severity:** Low 3.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 May 2026
- **Updated:** 23 Jun 2026
- **Also known as:** CLEANSTART-2026-RS53138, ECHO-e215-888a-4fed, GHSA-hm8q-7f3q-5f36, MINI-2mw8-876p-rm68, MINI-5xwh-x87f-p43x, MINI-f5xw-pv69-6586, MINI-fh2f-77f6-jhv7, MINI-jh2h-fhh5-v763, MINI-mx2j-m83p-22j9, MINI-mxv2-fv3h-xqgg, MINI-v7w8-ggj3-r6c3, MINI-vcqg-42mh-j68f

## What is CVE-2026-44459?

CVE-2026-44459 is a low-severity authentication bypass vulnerability in honojs hono, published on 13 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.18, 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. This vulnerability is fixed in 4.12.18.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-44459?

2 open source packages ship an affected version, including hono. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `hono` | npm | All versions | 4.12.18 |
| `hono` | npm | All versions | 4.12.18 |

Products: Hono Hono.

## How do I fix CVE-2026-44459?

Upgrade hono to 4.12.18 or later.

## Is CVE-2026-44459 being exploited?

There is no known exploitation of CVE-2026-44459 in the wild and no public exploit code.

## Other vulnerabilities in honojs hono

- [CVE-2026-27700](https://insights.sbomify.com/CVE-2026-27700/): Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo (high 8.2)
- [CVE-2026-22817](https://insights.sbomify.com/CVE-2026-22817/): JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass (high 8.2)
- [CVE-2026-22818](https://insights.sbomify.com/CVE-2026-22818/): JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback) (high 8.2)
- [CVE-2025-62610](https://insights.sbomify.com/CVE-2025-62610/): Hono Improperly Authorizes JWT Audience Validation (high 8.1)
- [CVE-2026-29045](https://insights.sbomify.com/CVE-2026-29045/): Hono: Arbitrary file access via serveStatic vulnerability (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44459 and fix it if it is affected.

What it is: CVE-2026-44459 is a low-severity authentication bypass vulnerability in honojs hono, published on 13 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-44459 in the wild and no public exploit code.

Affected packages and fixed versions:
- hono (npm): affected all versions; fixed in 4.12.18
- hono (npm): affected all versions; fixed in 4.12.18

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-44459/ (Markdown: https://insights.sbomify.com/CVE-2026-44459/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44459
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44459
- OSV: https://osv.dev/vulnerability/CVE-2026-44459

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44459/
Summaries are generated and may contain mistakes; the official description above is the record.