CVE-2026-126210 json
@hono/node-server: Backslash in the request path is parsed as a path separator, bypassing path-based access control at a reverse proxy
published 13d ago modified yesterday also EUVD-2026-124720 , GHSA-jpvv-r467-5p4w
- cvss
- 5.3
- 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 31%
- public exploits
- 0
- none known
Summary
@hono/node-server allows running the Hono application on Node.js. Prior to 1.19.18 and from 2.0.0 until 2.1.6, the server passes a raw request-target containing a backslash in its path to the WHATWG URL parser, which treats the backslash as a path separator and resolves dot segments. A reverse proxy, load balancer, or web application firewall that preserves the backslash and applies path-based rules to the original request can therefore permit a request that the application normalizes to a blocked route. This lets an unauthenticated client reach route content that the upstream component was intended to deny, while Hono application access controls are unaffected because they operate on the normalized path. This issue is fixed in versions 1.19.18 and 2.1.6.
Patch / fix
- npm @hono/node-server 1.19.18, 2.1.6
Is CVE-2026-126210 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- yesterday
Exploit prediction
0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-14).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @hono/node-server | >=2.0.0, <2.1.6 <1.19.18 |
2.1.6 1.19.18 |
Affected products
- honojs node-server
Classification
- Weakness
-
- CWE-436 Interpretation Conflict
References
-
github.com
/honojs/node-server/commit/3868998a805ae79216535ad3986c1e7228dee313
web
-
github.com
/honojs/node-server/commit/fb97395ec36af66567c76976e741110b02804d1c
web
-
github.com
/honojs/node-server/security/advisories/GHSA-jpvv-r467-5p4w
web, advisory
-
github.com
/honojs/node-server/releases/tag/v1.19.18
web
-
github.com
/honojs/node-server/releases/tag/v2.1.6
web
-
github.com
/honojs/node-server
package
Sources
- CVE List CVE-2026-126210
- GitHub Advisory GHSA-jpvv-r467-5p4w
- NVD CVE-2026-126210
- Maintainer advisory GHSA-jpvv-r467-5p4w
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/node-server published their own advisory on GitHub. Reviewed sources take precedence over it.