XSS in Hono
CVE-2026-56761
hono before 4.12.14 contains an html injection vulnerability in jsx server-side rendering that allows attackers to inject unintended html by using malformed attribute names. Attackers can craft specially crafted attribute keys containing characters like quotes or angle brackets to break html tag boundaries and inject arbitrary attributes or elements.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (19.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Hono — versions 0, 4.12.14
Weakness classification (CWE)
References
- github.com/honojs/hono/security/advisories/GHSA-458j-xx4x-4375 (vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/hono-html-injection-via-improper-jsx-attribute-nam… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-56761?
- CVE-2026-56761 is a medium-severity vulnerability in Hono, classified under Cross-site Scripting. CVSS score: 4.3/10. Published 2026-06-24.
- How severe is CVE-2026-56761?
- Medium severity. CVSS v3 base score is 4.3 out of 10.