← Vulnerability feed

Vulnerability record · CVE-2026-27700 · published 25 February 2026

CVE-2026-27700: Hono authentication bypass by spoofing vulnerability

Hono · Hono

Hono is a Web application framework that provides support for any JavaScript runtime. In versions 4.12.0 and 4.12.1, when using the AWS Lambda adapter (`hono/aws-lambda`) behind an Application Load Balancer (ALB), the `getConnInfo()` function incorrectly selected the first value from the `X-Forwarded-For` header. Because AWS ALB appends the real client IP address to the end of the `X-Forwarded-For` header, the first value can be attacker-controlled. This could allow IP-based access control mechanisms (such as the `ipRestriction` middleware) to be bypassed. Version 4.12.2 patches the issue.

7.5 CVSS 3.1 High EPSS 0.34% · top 74.8% CWE-290 · Authentication bypass by spoofingCWE-345 · Insufficient verification of data authenticity
7.5CVSS 3.1 base score
0.34%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

Description

Hono is a Web application framework that provides support for any JavaScript runtime. In versions 4.12.0 and 4.12.1, when using the AWS Lambda adapter (`hono/aws-lambda`) behind an Application Load Balancer (ALB), the `getConnInfo()` function incorrectly selected the first value from the `X-Forwarded-For` header. Because AWS ALB appends the real client IP address to the end of the `X-Forwarded-For` header, the first value can be attacker-controlled. This could allow IP-based access control mechanisms (such as the `ipRestriction` middleware) to be bypassed. Version 4.12.2 patches the issue.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/honojs/hono/commit/41adbf56e252c04611f8972364ac0887ae07a4c7 Patch
https://github.com/honojs/hono/releases/tag/v4.12.2 ProductRelease Notes
https://github.com/honojs/hono/security/advisories/GHSA-xh87-mx6m-69f3 Vendor Advisory

Track CVE-2026-27700 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-29045Hono vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using serveStatic together with r…EPSS 0.60%8.1CVE-2025-62610Hono improper authorization vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. In versions from 1.1.0 to before 4.10.2, Hono’s JWT Auth Middle…EPSS 0.38%7.5CVE-2025-58362Hono vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. Versions 4.8.0 through 4.9.5 contain a flaw in the getPath util…EPSS 0.53%6.5CVE-2026-59896Hono race condition vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. From 4.11.8 before 4.12.27, hono/jsx did not isolate context va…EPSS 0.30%6.5CVE-2026-47673Hono improper authorization vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the jwt and jwk middlewares do not verify tha…EPSS 0.25%6.5CVE-2026-44456Hono uncontrolled resource consumption vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.16, bodyLimit() does not reliably enforce maxSize…EPSS 0.28%6.5CVE-2026-29085Hono injection vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using streamSSE() in Streaming He…EPSS 0.29%6.5CVE-2026-24398Hono vulnerabilityHono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.11.7, IP Restriction Middleware in Hono is v…EPSS 0.35%

Source: NIST National Vulnerability Database (record CVE-2026-27700), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.