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OpenAdvisories
High · 8.2 CVE-2026-22818 EUVD-2026-2017GHSA-3vhc-576x-3qv4

JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback)

Published Jan 13, 2026 · Updated Jan 15, 2026 · Assigned by GitHub_M

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.11.4, there is a flaw in Hono’s JWK/JWKS JWT verification middleware allowed the algorithm specified in the JWT header to influence signature verification when the selected JWK did not explicitly define an algorithm. This could enable JWT algorithm confusion and, in certain configurations, allow forged tokens to be accepted. The JWK/JWKS JWT verification middleware has been updated to require an explicit allowlist of asymmetric algorithms when verifying tokens. The middleware no longer derives the verification algorithm from untrusted JWT header values. This vulnerability is fixed in 4.11.4.

Affected products

VendorProductAffectedFixed
honojs hono < 4.11.4 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling langfuse-3-worker 3.146.0-r1 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm hono < 4.11.4 4.11.4 GHSA-3vhc-576x-3qv4

Advisories 1

References