CVE-2026-44455 Hono: Unvalidated JSX Tag Names in hono/jsx May Allow HTML Injection
Attackers can inject malicious HTML via unvalidated JSX tag names in Hono's server-side rendering, potentially leading to XSS.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-44455?
CVE-2026-44455 is a medium-severity cross-site scripting vulnerability in honojs hono, published on 13 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.16, Improper handling of JSX element tag names in hono/jsx allowed unvalidated tag names to be directly inserted into the generated HTML output. When untrusted input is used as a tag name via the programmatic jsx() or createElement() APIs during server-side rendering, specially crafted values may break out of the intended element context and inject unintended HTML. This vulnerability is fixed in 4.12.16.
Weakness: CWE-74
Which versions are affected by CVE-2026-44455?
2 open source packages ship an affected version, including hono. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
hono npm | All versions | 4.12.16 |
hono npm | All versions | 4.12.16 |
Products include Hono Hono.
How do I fix CVE-2026-44455?
Upgrade hono to 4.12.16 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-44455 being exploited?
There is no known exploitation of CVE-2026-44455 in the wild and no public exploit code.
Other vulnerabilities in honojs hono
- CVE-2026-27700 Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo
- CVE-2026-22817 JWT Algorithm Confusion via Unsafe Default (HS256) in Hono JWT Middleware Allows Token Forgery and Auth Bypass
- CVE-2026-22818 JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback)
- CVE-2025-62610 Hono Improperly Authorizes JWT Audience Validation
- CVE-2026-29045 Hono: Arbitrary file access via serveStatic vulnerability
Sources
Also known as CLEANSTART-2026-FO60758, CLEANSTART-2026-XB47365, ECHO-1ec7-9d29-a202, GHSA-69xw-7hcm-h432, MINI-7j3p-44f3-279h, MINI-8585-wrp8-hm8w and 8 more.