CVE-2026-54286 json
Hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`)
published 5mo ago modified 17d ago also EUVD-2026-38327 , GHSA-wwfh-h76j-fc44
- cvss
- 5.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 38%
- public exploits
- 0
- none known
Summary
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, on Windows hosts, an encoded backslash (%5C) in the request path decodes to \, which the Windows path resolver treats as a separator. serve-static then resolves a single URL segment such as admin\secret.txt into a nested file under the root and serves it, letting an attacker read static files meant to be protected behind prefix-mounted middleware. This vulnerability is fixed in 4.12.25.
Patch / fix
- npm hono 4.12.25
- hono hono 4.12.25
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4mo ago
Exploit prediction
0.43% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| GitHub | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | hono | <4.12.25 |
4.12.25 |
Affected products
- honojs hono
Classification
- Weakness
-
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory
References
-
github.com
/honojs/hono/security/advisories/GHSA-wwfh-h76j-fc44
web, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-54286
advisory
-
github.com
/honojs/hono
package
Sources
- CVE List CVE-2026-54286
- GitHub Advisory GHSA-wwfh-h76j-fc44
- NVD CVE-2026-54286
- Maintainer advisory GHSA-wwfh-h76j-fc44
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of honojs/hono published their own advisory on GitHub. Reviewed sources take precedence over it.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.