honojs hono up to 4.12.1 getConnInfo X-Forwarded-For data authenticity

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in honojs hono up to 4.12.1. Affected by this issue is the function getConnInfo. Executing a manipulation of the argument X-Forwarded-For can lead to data authenticity. This vulnerability appears as CVE-2026-27700. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in honojs hono up to 4.12.1. This vulnerability affects the function getConnInfo. The manipulation of the argument X-Forwarded-For with an unknown input leads to a data authenticity vulnerability. The CWE definition for the vulnerability is CWE-345. The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-27700 since 02/23/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

Upgrading to version 4.12.2 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 41adbf56e252c04611f8972364ac0887ae07a4c7 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CNA Base Score: 8.2
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Data authenticity
CWE: CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: hono 4.12.2
Patch: 41adbf56e252c04611f8972364ac0887ae07a4c7

Timelineinfo

02/23/2026 CVE reserved
02/25/2026 +2 days Advisory disclosed
02/25/2026 +0 days VulDB entry created
03/03/2026 +6 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-xh87-mx6m-69f3
Status: Confirmed

CVE: CVE-2026-27700 (🔒)
GCVE (CVE): GCVE-0-2026-27700
GCVE (VulDB): GCVE-100-347788

Entryinfo

Created: 02/25/2026 17:33
Updated: 03/03/2026 10:08
Changes: 02/25/2026 17:33 (68), 03/03/2026 10:08 (9)
Complete: 🔍
Cache ID: 216::103

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