CVE-2026-24771: Hono Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-9r54-q6cx-xmh5
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CVSS 4.7
CWE-79
Published
Advisory Summary

CVE-2026-24771 is a MODERATE (CVSS 4.7) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Hono libraries in the npm ecosystem. The issue involves hono vulnerable to xss through errorboundary component. Remediation is available by upgrading affected packages to version 4.11.7.

CVE-2026-24771 at a Glance

CVE Identifier CVE-2026-24771
GHSA Identifier GHSA-9r54-q6cx-xmh5
Severity MODERATE
CVSS v3.1 Base Score 4.7
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Hono
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 4.7

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-24771

To remediate this vulnerability, upgrade all affected Hono dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

hono fixed: 4.11.7 
npm install hono@4.11.7
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls hono

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-24771, inspect your project dependencies using npm:

npm ls hono

Analyze the terminal output to locate any version of Hono in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.11.7), your application is affected.

Note: The npm ls hono command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Hono, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary A Cross-Site Scripting (XSS) vulnerability exists in the `ErrorBoundary` component of the hono/jsx library. Under certain usage patterns, untrusted user-controlled strings may be rendered as raw HTML, allowing arbitrary script execution in the victim's browser. ## Details The issue is in the `ErrorBoundary` component (`src/jsx/components.ts`). `ErrorBoundary` previously forced certain rendered output paths to be treated as raw HTML, bypassing the library's default escaping behavior. This could result in unescaped rendering when developers pass user-controlled strings directly as children, or when fallbackRender returns user-controlled strings (for example, reflecting error messages that contain attacker input). This vulnerability is only exploitable when an application renders untrusted user input within `ErrorBoundary` without appropriate escaping or sanitization. ## Impact Successful exploitation may allow attackers to execute arbitrary JavaScript in the victim’s browser (reflected XSS). Depending on the application context, this can lead to actions such as session compromise, data exfiltration, or performing unauthorized actions as the victim. ## Affected Components * hono/jsx: `ErrorBoundary` component

CVE-2026-24771 Affected Hono Versions

1 component(s)
Fixed Versions:
4.11.7
Product / Package Ecosystem Affected Versions Fixed Version
hono
npm/hono
npm
< 4.11.7
4.11.7

References

GitHub Advisory / Wiki ADVISORY
https://github.com/honojs/hono/security/advisories/GHSA-9r54-q6cx-xmh5
NVD — CVE-2026-24771 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-24771
Security Fix Commit FIX COMMIT
https://github.com/honojs/hono/commit/2cf60046d730df9fd0aba85178f3ecfe8212d990
Hono Source Repository REPOSITORY
https://github.com/honojs/hono

Frequently Asked Questions

What is CVE-2026-24771?
CVE-2026-24771 is a security vulnerability in Hono involving Hono vulnerable to XSS through ErrorBoundary component under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Hono versions are affected?
Affected versions include releases prior to 4.11.7 across affected packages: hono.
What version fixes CVE-2026-24771?
Upgrading to 4.11.7 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hono affected?
Yes, hono is affected in releases prior to 4.11.7. Upgrade your dependency to 4.11.7 or later.
What is the CVSS score of CVE-2026-24771?
CVE-2026-24771 has a CVSS v3.1 base score of 4.7 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-24771?
CVE-2026-24771 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check npm dependencies for CVE-2026-24771?
Run the dependency tree command: 'npm ls hono'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9r54-q6cx-xmh5",
  "modified" : "2026-01-28T16:10:22Z",
  "published" : "2026-01-28T16:10:22Z",
  "aliases" : [ "CVE-2026-24771" ],
  "summary" : "Hono vulnerable to XSS through ErrorBoundary component ",
  "details" : "## Summary\n\nA Cross-Site Scripting (XSS) vulnerability exists in the `ErrorBoundary` component of the hono/jsx library. Under certain usage patterns, untrusted user-controlled strings may be rendered as raw HTML, allowing arbitrary script execution in the victim's browser.\n\n## Details\n\nThe issue is in the `ErrorBoundary` component (`src/jsx/components.ts`). `ErrorBoundary` previously forced certain rendered output paths to be treated as raw HTML, bypassing the library's default escaping behavior. This could result in unescaped rendering when developers pass user-controlled strings directly as children, or when fallbackRender returns user-controlled strings (for example, reflecting error messages that contain attacker input).\n\nThis vulnerability is only exploitable when an application renders untrusted user input within `ErrorBoundary` without appropriate escaping or sanitization.\n\n## Impact\n\nSuccessful exploitation may allow attackers to execute arbitrary JavaScript in the victim’s browser (reflected XSS). Depending on the application context, this can lead to actions such as session compromise, data exfiltration, or performing unauthorized actions as the victim.\n\n## Affected Components\n\n* hono/jsx: `ErrorBoundary` component",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "hono"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.11.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/honojs/hono/security/advisories/GHSA-9r54-q6cx-xmh5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24771"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/honojs/hono/commit/2cf60046d730df9fd0aba85178f3ecfe8212d990"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/honojs/hono"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-28T16:10:22Z",
    "nvd_published_at" : "2026-01-27T20:16:24Z"
  }
}