CVE-2026-59897

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.3.3 before 4.12.27, the AWS API Gateway v1 adapter can drop a distinct repeated request header value because it de-duplicates values using a substring comparison instead of an exact match, so middleware or application logic that depends on the complete X-Forwarded-For chain, rate limiting, audit logging, or proxy-chain validation can receive incomplete data. This issue is fixed in version 4.12.27.

CVSS 3.1

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 7% of CVEs (scores of 2026-10-25)

CWE

CWE-348

Published

2026-07-08

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Affected

• hono:hono

Packages (OSV)

References

• https://github.com/honojs/hono/commit/aa921770d09bc35970362d5a2630a878f6d982fd
• https://github.com/honojs/hono/releases/tag/v4.12.27
• https://github.com/honojs/hono/security/advisories/GHSA-xgm2-5f3f-mvvc

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