CVE-2026-44455: Hono Hono/jsx Has Unvalidated JSX Tag Vulnerability

MODERATE
Advisory Identifier: GHSA-69xw-7hcm-h432
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CVSS 4.7
CWE-74
Published
Advisory Summary

CVE-2026-44455 is a MODERATE (CVSS 4.7) hono/jsx has unvalidated jsx tag vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')) affecting Hono libraries in the npm ecosystem. The issue involves hono/jsx has unvalidated jsx tag names that may allow html injection. Remediation is available by upgrading affected packages to version 4.12.16.

CVE-2026-44455 at a Glance

CVE Identifier CVE-2026-44455
GHSA Identifier GHSA-69xw-7hcm-h432
Severity MODERATE
CVSS v3.1 Base Score 4.7
CWE Classification CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
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-2026-44455

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: 4.12.16 
npm install hono@4.12.16
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-2026-44455, 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 4.12.16), 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-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), where the product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. 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 Improper handling of JSX element tag names in hono/jsx allowed unvalidated tag names to be directly inserted into the generated HTML output. When untrusted input is used as a tag name via the programmatic `jsx()` or `createElement()` APIs during server-side rendering, specially crafted values may break out of the intended element context and inject unintended HTML. ## Details When rendering JSX elements to HTML strings, attribute values are escaped and attribute names are validated. However, element tag names were previously inserted into the output without validation. If a tag name contains characters such as `<`, `>`, quotes, or whitespace, it may alter the structure of the generated HTML. For example, malformed tag names can: * Break out of the intended element and introduce unintended HTML elements * Inject attributes or event handlers into the rendered output This issue arises when untrusted input (such as query parameters or database content) is used as JSX tag names via `jsx()` or `createElement()` during server-side rendering. ## Impact An attacker who can control tag names used in JSX rendering may inject unintended HTML into the generated output. This may lead to: * Injection of unexpected HTML elements or attributes * Corruption of the HTML structure * Cross-site scripting (XSS) when combined with unsafe usage patterns This issue only affects applications that construct JSX tag names from untrusted input. Applications using static or allowlisted tag names are not affected.

CVE-2026-44455 Affected Hono Versions

1 component(s)
Fixed Versions:
4.12.16
Product / Package Ecosystem Affected Versions Fixed Version
hono
npm/hono
npm
< 4.12.16
4.12.16

References

GitHub Advisory / Wiki ADVISORY
https://github.com/honojs/hono/security/advisories/GHSA-69xw-7hcm-h432
NVD — CVE-2026-44455 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44455
Hono Source Repository REPOSITORY
https://github.com/honojs/hono

Frequently Asked Questions

What is CVE-2026-44455?
CVE-2026-44455 is a security vulnerability in Hono involving hono/jsx has Unvalidated JSX Tag Names that May Allow HTML Injection under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection').
Which Hono versions are affected?
Affected versions include releases prior to 4.12.16 across affected packages: hono.
What version fixes CVE-2026-44455?
Upgrading to 4.12.16 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hono affected?
Yes, hono is affected in releases prior to 4.12.16. Upgrade your dependency to 4.12.16 or later.
What is the CVSS score of CVE-2026-44455?
CVE-2026-44455 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-2026-44455?
CVE-2026-44455 is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.).
How can I check npm dependencies for CVE-2026-44455?
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-69xw-7hcm-h432",
  "modified" : "2026-05-14T20:31:59Z",
  "published" : "2026-05-06T23:49:43Z",
  "aliases" : [ "CVE-2026-44455" ],
  "summary" : "hono/jsx has Unvalidated JSX Tag Names that May Allow HTML Injection",
  "details" : "## Summary\n\nImproper handling of JSX element tag names in hono/jsx allowed unvalidated tag names to be directly inserted into the generated HTML output.\n\nWhen untrusted input is used as a tag name via the programmatic `jsx()` or `createElement()` APIs during server-side rendering, specially crafted values may break out of the intended element context and inject unintended HTML.\n\n## Details\n\nWhen rendering JSX elements to HTML strings, attribute values are escaped and attribute names are validated. However, element tag names were previously inserted into the output without validation.\n\nIf a tag name contains characters such as `<`, `>`, quotes, or whitespace, it may alter the structure of the generated HTML.\n\nFor example, malformed tag names can:\n\n* Break out of the intended element and introduce unintended HTML elements\n* Inject attributes or event handlers into the rendered output\n\nThis issue arises when untrusted input (such as query parameters or database content) is used as JSX tag names via `jsx()` or `createElement()` during server-side rendering.\n\n## Impact\n\nAn attacker who can control tag names used in JSX rendering may inject unintended HTML into the generated output.\n\nThis may lead to:\n\n* Injection of unexpected HTML elements or attributes\n* Corruption of the HTML structure\n* Cross-site scripting (XSS) when combined with unsafe usage patterns\n\nThis issue only affects applications that construct JSX tag names from untrusted input. Applications using static or allowlisted tag names are not affected.",
  "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" : "4.12.16"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/honojs/hono/security/advisories/GHSA-69xw-7hcm-h432"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44455"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/honojs/hono"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-06T23:49:43Z",
    "nvd_published_at" : "2026-05-13T16:16:57Z"
  }
}