Is there a public exploit for CVE-2026-84363?

No public exploit for CVE-2026-84363 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-84363?

CVE-2026-84363 scores CVSS 5.9 (v3.1), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.45%.

What does CVE-2026-84363 affect?

CVE-2026-84363 affects honojs hono.

5.9 Medium

Hono is a Web application framework that provides support for any JavaScript runtime.

CVE-2026-84363

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.5, Hono's query helpers treat a question mark after a literal hash fragment as the start of a query string, so the application can read request parameters that browsers, new URL(), reverse proxies, filtering rules, parameter allow and deny lists, access logging, request validation, and other middleware do not observe. The Cache Middleware removes the fragment when building its cache key, allowing a response influenced by parameters inside the fragment to be stored under a key that omits those parameters and later served to other users. This can bypass filtering and auditing, poison cached responses, and enable stored cross-site scripting when an affected parameter is reflected into cached HTML without escaping. Exploitation requires a runtime and intermediary path that passes a literal hash character through to the request URL; Cloudflare Workers and intermediaries that strip fragments are not affected. This issue is fixed in version 4.13.5.

Assessment

CVSS: 5.9 (v3.1)
Severity: Medium
EPSS: 0.45% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 1 September 2026
Last updated: 9 September 2026
Affected: honojs · hono
Weakness: CWE-444
Assigner: security-advisories@github.com

CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

At the source

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