CVE-2026-93981: Hono Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-hxh3-vqpv-xpqv
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CVSS 4.7
CWE-79
Published
Advisory Summary

CVE-2026-93981 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/jsx renders plain strings unescaped in boundary components, leading to xss. Remediation is available by upgrading affected packages to version 4.13.7.

CVE-2026-93981 at a Glance

CVE Identifier CVE-2026-93981
GHSA Identifier GHSA-hxh3-vqpv-xpqv
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-2026-93981

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: 4.13.7 
npm install hono@4.13.7
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-2026-93981, 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 4.13.7), 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 `hono/jsx` does not HTML-escape a plain string placed directly as a child or `fallback` of `Suspense` or `ErrorBoundary`, as the only child of a `Context.Provider`, or as the root value of `renderToString()` / `renderToReadableStream()` from `hono/jsx/dom/server`. Such a string is emitted as markup instead of text. ### Details These paths stringify their input and treat the result as already-escaped HTML, so a plain string passes through unchanged. Notable cases: - `Suspense`: a string child, or a string `fallback` while a child suspends. With streaming, the fallback reaches the browser in the initial chunk. - `ErrorBoundary`: a string child alongside an asynchronous sibling. The all-synchronous case was fixed in 4.11.7 (GHSA-9r54-q6cx-xmh5). - `Context.Provider`: a single string child. Multiple children are escaped. - `hono/jsx/dom/server`: a string, or an array containing strings, passed as the root. A lone `{children}` forwarded by a wrapper component is enough to reach these paths. Strings wrapped in an element, values from `raw()` or the `html` helper, and client-side rendering with `hono/jsx/dom` are not affected. ### Impact An attacker who controls a string rendered in an affected position can inject arbitrary HTML into the server-rendered page, leading to cross-site scripting under the application's origin. This issue affects applications that render untrusted strings directly in one of the positions above during server-side rendering.

CVE-2026-93981 Affected Hono Versions

1 component(s)
Fixed Versions:
4.13.7
Product / Package Ecosystem Affected Versions Fixed Version
hono
npm/hono
npm
< 4.13.7
4.13.7

References

GitHub Advisory / Wiki ADVISORY
https://github.com/honojs/hono/security/advisories/GHSA-hxh3-vqpv-xpqv
NVD — CVE-2026-93981 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-93981
Security Fix Commit FIX COMMIT
https://github.com/honojs/hono/commit/2b8ed402cdab6dfc5e829b480806dcd8db94161e
Hono Source Repository REPOSITORY
https://github.com/honojs/hono
Hono Release RELEASE
https://github.com/honojs/hono/releases/tag/v4.13.7
www.vulncheck.com/advisories/hono-jsx... WEB
https://www.vulncheck.com/advisories/hono-jsx-before-4.13.7-cross-site-scripting-via-unescaped-strings

Frequently Asked Questions

What is CVE-2026-93981?
CVE-2026-93981 is a security vulnerability in Hono involving hono/jsx renders plain strings unescaped in boundary components, leading to XSS 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 4.13.7 across affected packages: hono.
What version fixes CVE-2026-93981?
Upgrading to 4.13.7 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hono affected?
Yes, hono is affected in releases prior to 4.13.7. Upgrade your dependency to 4.13.7 or later.
What is the CVSS score of CVE-2026-93981?
CVE-2026-93981 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-2026-93981?
CVE-2026-93981 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-2026-93981?
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-hxh3-vqpv-xpqv",
  "modified" : "2026-09-30T23:46:16Z",
  "published" : "2026-09-30T23:46:16Z",
  "aliases" : [ "CVE-2026-93981" ],
  "summary" : "hono/jsx renders plain strings unescaped in boundary components, leading to XSS",
  "details" : "### Summary\n\n`hono/jsx` does not HTML-escape a plain string placed directly as a child or `fallback` of `Suspense` or `ErrorBoundary`, as the only child of a `Context.Provider`, or as the root value of `renderToString()` / `renderToReadableStream()` from `hono/jsx/dom/server`. Such a string is emitted as markup instead of text.\n\n### Details\n\nThese paths stringify their input and treat the result as already-escaped HTML, so a plain string passes through unchanged. Notable cases:\n\n- `Suspense`: a string child, or a string `fallback` while a child suspends. With streaming, the fallback reaches the browser in the initial chunk.\n- `ErrorBoundary`: a string child alongside an asynchronous sibling. The all-synchronous case was fixed in 4.11.7 (GHSA-9r54-q6cx-xmh5).\n- `Context.Provider`: a single string child. Multiple children are escaped.\n- `hono/jsx/dom/server`: a string, or an array containing strings, passed as the root.\n\nA lone `{children}` forwarded by a wrapper component is enough to reach these paths. Strings wrapped in an element, values from `raw()` or the `html` helper, and client-side rendering with `hono/jsx/dom` are not affected.\n\n### Impact\n\nAn attacker who controls a string rendered in an affected position can inject arbitrary HTML into the server-rendered page, leading to cross-site scripting under the application's origin.\n\nThis issue affects applications that render untrusted strings directly in one of the positions above during server-side rendering.",
  "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" : [ {
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      "type" : "ECOSYSTEM",
      "events" : [ {
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      } ]
    } ]
  } ],
  "references" : [ {
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    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-93981"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/honojs/hono/commit/2b8ed402cdab6dfc5e829b480806dcd8db94161e"
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    "url" : "https://github.com/honojs/hono/releases/tag/v4.13.7"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/hono-jsx-before-4.13.7-cross-site-scripting-via-unescaped-strings"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-30T23:46:16Z",
    "nvd_published_at" : null
  }
}