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.
CVE-2026-59895
This medium-severity CVE scores 6.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.1
- EG Score
- 6.1(medium)
- EPSS
- 8.5%
- KEV
- Not listed
Published
July 8, 2026
Last Modified
July 10, 2026
Advisory Details (3)
Auto-updated Jul 8, 2026Server-Side XSS via JSX Escaping Bypass in cx() Utility · Advisory · honojs/hono · GitHub
https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59v4.12.27
Patch available: honojs/hono v4.12.27
https://github.com/honojs/hono/releases/tag/v4.12.27commit cd3f6f7194f0 (honojs/hono)
Patch available: honojs/hono v4.12.27 (contains commit cd3f6f7194f0)
https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fcWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 10× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 22:32 UTCEG score recompute
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-10 20:30 UTCEG score recompute
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 18:28 UTCEG score recompute
- 2026-07-08 16:25 UTCEG score recompute
- 2026-07-08 16:24 UTCMITRE cvelistV5first tracked
Frequently asked(5)
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-59895
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