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Advisory severityMedium6.1Red Hat Linux

Medium [CVE-2026-59895] Arbitrary markup injection via improper handling of class names in server-side rendering.

This medium-severity Red Hat Linux advisory covers CVE-2026-59895 affecting Migration Toolkit for Applications 8, Red Hat Ansible Automation Platform 2, Red Hat Developer Hub 1.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-59895 Source published Source updated

VulniPulse record published Record updated

CVE-2026-59895
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

Summary

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.

This could result in Cross-Site Scripting (XSS) attacks, where malicious scripts can be executed in a user's browser. Red Hat severity: Moderate — CVSS 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Weakness: CWE-79. Affected Red Hat products: Migration Toolkit for Applications 8; Red Hat Ansible Automation Platform 2; Red Hat Developer Hub 1; Red Hat OpenShift Dev Spaces.

Red Hat lists Red Hat Hardened Images as not affected. Red Hat does not currently list a fixing RHSA for this CVE.

Is CVE-2026-59895 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-59895 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-59895?

Upgrade to a fixed release named by Red Hat:

  • 4.12.27

Confirm against the vendor advisory before you patch.

Affected versions
  • < 4.0.0
  • < 4.12.27

Official advisory · high-confidence parse· fetched 1 day ago·verify at source

Fixed versions
  • 4.12.27

Official advisory · high-confidence parse· fetched 1 day ago·verify at source

Mitigation

Upgrade to a fixed release: 4.12.27. That is the remediation for this advisory.

The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.

Official advisory · high-confidence parse· fetched 1 day ago·verify at source

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