CVE-2026-47676: honojs hono · HTTP Request/Response Smuggling
Affects honojs honoSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium : upgrade to 4.12.21 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.12.21
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 28 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade hono and honojs/hono to 4.12.21.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| honojshono | Affected
| Fixed in
|
npmhonojs/honopkg:npm/honojs/honoOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade honojs hono to version 4.12.21 or later, where this vulnerability is fixed. Since the vendor has released a fixed version, applying this official update is the recommended remediation. Patch status is confirmed by the version fix note. No additional mitigation guidance or temporary workarounds are provided.
Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, app.mount() strips the mount prefix from the incoming request path using the raw URL pathname, while route matching is performed against the percent-decoded path. This inconsistency causes the prefix to be stripped at the wrong position when the path contains percent-encoded multi-byte characters, resulting in the mounted sub-application receiving an incorrect path. This vulnerability is fixed in 4.12.21.