XSS in Honojs Hono
CVE-2026-93981
hono before 4.13.7 fails to HTML-escape plain strings rendered by hono/jsx as a child or fallback of Suspense, as a string child of ErrorBoundary alongside an asynchronous sibling, as the single child of a Context.Provider, or as the root value passed to renderToString() or renderToReadableStream() from hono/jsx/dom/server. These paths stringify their input and treat the result as already-escaped markup, so an attacker who controls such a string during server-side rendering can inject arbitrary HTML and execute script under the application's origin.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (13.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 13.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/honojs/hono/security/advisories/GHSA-hxh3-vqpv-xpqv (vendor-advisory)
- www.vulncheck.com/advisories/hono-jsx-before-4.13.7-cross-site-scripting-via-un… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-93981?
- CVE-2026-93981 is a medium-severity vulnerability in Honojs Hono, classified under Cross-site Scripting. CVSS score: 4.7/10. Published 2026-09-19.
- How severe is CVE-2026-93981?
- Medium severity. CVSS v3 base score is 4.7 out of 10.