CVE-2026-59895 | BDVDB-2026-346385 Detail

honojshono

Description#

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.

Impact#

Per CVSS v3.1: confidentiality impact low, integrity impact low, availability impact none. Attack vector: network.

Weaknesses#

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116 Improper Encoding or Escaping of Output

References#

Exploit#

No public exploit known

History#

Version 12026-07-08Record published in the CVE List.

Published

Published: 2026-07-08
Last modified: 2026-07-08

Vendor information

Vendor: honojs
Product: hono

All honojs vulnerabilities

Score

6.1 Medium

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 26.0.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Cross-Site Scripting

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
>= 4.0.0, < 4.12.27
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

6.1 Medium

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	Required
Scope	Changed
Confidentiality	Low
Integrity	Low
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).