Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo
Exploitation and risk
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cve-program · CVE-2026-27700
PublishedHono 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.
- Source published
- 25 Feb 2026 15:01:44 UTC
- Source modified
- 27 Feb 2026 17:01:28 UTC
- Saved here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 3.1 · 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
euvd · EUVD-2026-8644
PublishedHono 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.
Additional publisher context
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Feb 25, 2026, 3:01:44 PM
dateUpdated: Feb 27, 2026, 5:01:28 PM
- Source published
- Feb 25, 2026, 3:01:44 PM (timezone not stated)
- Source modified
- Feb 27, 2026, 5:01:28 PM (timezone not stated)
- Saved here
- 13 Nov 2026 10:57:18 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
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EUVD CVSS 3.1 · 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
nvd · CVE-2026-27700
PublishedHono 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.
Additional publisher context
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Analyzed
Weakness classifications: CWE-290 · CWE-345
Original publisher date fields
published: 2026-02-25T16:23:26.440
lastModified: 2026-06-17T10:27:32.397
1 source CPE criteria · context only
- cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*
The original JSON retains the logical configuration operators, exclusions and version bounds.
- Source published
- 25 Feb 2026 16:23:26 UTC
- Source modified
- 17 Jun 2026 10:27:32 UTC
- Saved here
- 25 Oct 2026 06:17:33 UTC
- Source terms
- NIST NVD usage terms; underlying source attribution retained
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CVSS 3.1 · [email protected] · Secondary · 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
osv · GHSA-xh87-mx6m-69f3
Published## Summary 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. ## Details In ALB environments, AWS appends the actual client IP address to the end of any existing `X-Forwarded-For` header value. However, the previous implementation of `getConnInfo()` extracted the leftmost IP address: ```ts address = xff.split(',')[0].trim() ``` If a client sent: ``` X-Forwarded-For: <spoofed-ip> ``` ALB would forward: ``` X-Forwarded-For: <spoofed-ip>, <real-client-ip> ``` Since the implementation selected the first value, the spoofed IP address was trusted. This affected applications using: ```ts ipRestriction(getConnInfo, { allowList: [...] }) ``` or any custom middleware relying on `getConnInfo(c).remote.address` for authorization decisions. The issue only affects deployments using the AWS Lambda adapter behind an ALB. API Gateway (v1/v2) and Lambda Function URLs are not affected, as they use AWS-provided source IP values from `requestContext`. ## Impact An unauthenticated remote attacker could bypass IP-based access restrictions by supplying a crafted `X-Forwarded-For` header. This may allow access to resources that were intended to be restricted by IP address. Only applications deployed behind an ALB and relying on `getConnInfo()` for IP-based authorization are affected.
- Source published
- 25 Feb 2026 18:02:19 UTC
- Source modified
- 10 Sep 2026 03:50:36 UTC
- Saved here
- 24 Oct 2026 13:17:17 UTC
- Source terms
- GitHub Advisory Database · CC-BY-4.0
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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Publisher rating · HIGH