CVE-2026-93981
mediumpriority · track · 19EPSS 0.002 · 13 %ileUSEPSS · scored 2026-10-21
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 0.6–4.7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-hxh3-vqpv-xpqvhono/jsx renders plain strings unescaped in boundary components, leading to XSS2026-09-30ghsa · osvUS
### Summary `hono/jsx` does not HTML-escape a plain string placed directly as a child or `fallback` of `Suspense` or `ErrorBoundary`, as the only child of a `Context.Provider`, or as the root value of `renderToString()` / `renderToReadableStream()` from `hono/jsx/dom/server`. Such a string is emitted as markup instead of text. ### Details These paths stringify their input and treat the result as already-escaped HTML, so a plain string passes through unchanged. Notable cases: - `Suspense`: a string child, or a string `fallback` while a child suspends. With streaming, the fallback reaches the browser in the initial chunk. - `ErrorBoundary`: a string child alongside an asynchronous sibling. The all-synchronous case was fixed in 4.11.7 (GHSA-9r54-q6cx-xmh5). - `Context.Provider`: a single string child. Multiple children are escaped. - `hono/jsx/dom/server`: a string, or an array containing strings, passed as the root. A lone `{children}` forwarded by a wrapper component is enough to reach these paths. Strings wrapped in an element, values from `raw()` or the `html` helper, and client-side rendering with `hono/jsx/dom` are not affected. ### Impact An attacker who controls a string rendered in an affected position can inject arbitrary HTML into the server-rendered page, leading to cross-site scripting under the application's origin. This issue affects applications that render untrusted strings directly in one of the positions above during server-side rendering.
sources
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references (2) nvd
External citations — patches, advisories, analysis.
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