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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-59895

29
FAUCET Score

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the input, allowing untrusted className values used in a JSX class attribute during server-side rendering to break out of the attribute and inject arbitrary markup. This issue is fixed in version 4.12.27.

First published: Jul 8, 2026Last modified: Jul 8, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 4.0.0, < 4.12.27CPE matchmatch criteria
cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 3.1

6.1MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
2.7
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.20%
Probability of exploitation in next 30 days
EPSS Percentile
9.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0020 is in the 10th percentile among its peer group of 26,220 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: honoFixed in: 4.12.27

Vendor Advisories (1)

npmGHSA-w62v-xxxg-mg59medium

Hono: Server-Side XSS via JSX Escaping Bypass in cx() Utility

Jul 21, 2026

References

github.com / honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc
Patch
github.com / honojs/hono/releases/tag/v4.12.27
Release Notes
github.com / honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59
Vendor Advisory