CVE-2026-54289

Hono: Lambda@Edge adapter keeps only the last value of a repeated request header, dropping the rest

Published Jun 22, 2026 CVSS 3.1 · 4.8 Medium EPSS < 1% KEV · Not listed
Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on AWS Lambda@Edge, CloudFront delivers a request header that appears more than once as several separate entries. The adapter writes each value with Headers.set instead of Headers.append, so every value overwrites the previous one and only the last reaches the application. Repeated request headers such as X-Forwarded-For, Forwarded, and Via are silently truncated to a single value. Request middleware sees only the last value of a repeated header instead of the full chain. For applications that base access control on the X-Forwarded-For chain, this can weaken or alter that decision; for auditing, hop history is lost. This vulnerability is fixed in 4.12.25.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-wgpf-jwqj-8h8p hono: Lambda@Edge adapter keeps only the last value of a repeated request header, dropping the rest
History
Type Values Removed Values Added
First Time appeared Hono
Hono hono
Vendors & Products Hono
Hono hono
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on AWS Lambda@Edge, CloudFront delivers a request header that appears more than once as several separate entries. The adapter writes each value with Headers.set instead of Headers.append, so every value overwrites the previous one and only the last reaches the application. Repeated request headers such as X-Forwarded-For, Forwarded, and Via are silently truncated to a single value. Request middleware sees only the last value of a repeated header instead of the full chain. For applications that base access control on the X-Forwarded-For chain, this can weaken or alter that decision; for auditing, hop history is lost. This vulnerability is fixed in 4.12.25.
Title Hono: Lambda@Edge adapter keeps only the last value of a repeated request header, dropping the rest
Weaknesses CWE-348
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jun 22, 2026, 6:19 PM
Reserved
Jun 12, 2026, 5:46 PM
Status
Deferred
Published
Jun 22, 2026, 6:16 PM
Modified
Oct 25, 2026, 11:10 PM