@hono/node-server has authorization bypass for protected static paths via encoded slashes in Serve Static Middleware

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2026-29087: 0.36% estimated exploitation activity in the next 30 days; percentile 30.22 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When using @hono/node-server's static file serving together with route-based middleware protections (e.g. protecting /admin/), inconsistent URL decoding can allow protected static resources to be accessed without authorization. In particular, paths containing encoded slashes (%2F) may be evaluated differently by routing/middleware matching versus static file path resolution, enabling a bypass where middleware does not run but the static file is still served. Details The routing layer and the node-server static handler normalize request paths differently. The router preserves %2F as a literal string when matching routes, while the static handler decodes %2F into / before resolving the filesystem path. Example request: - /admin%2Fsecret.html This may: - fail to match middleware intended for /admin/, but - still be resolved by the static handler as /admin/secret.html under the configured static root. This does not allow access outside the configured static root and is not a path…

Published by the source

4 Mar 2026, 20:05 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:43 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wc8c-qw6v-h7f6

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wc8c-qw6v-h7f6

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# Patch Next advisory brief: CVE-2026-29087

Advisory: @hono/node-server has authorization bypass for protected static paths via encoded slashes in Serve Static Middleware
IDs: CVE-2026-29087, GHSA-wc8c-qw6v-h7f6
Record: https://patchnext.com/advisories/cve-2026-29087 (revision 2, source checked 26 Oct 2026, 12:43 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @hono/node-server 1.19.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @hono/node-server: affected < 1.19.10; fixed in 1.19.10

## Suggested inspection (read-only)
- `npm ls @hono/node-server --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @hono/node-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-wc8c-qw6v-h7f6 (OSV record GHSA-wc8c-qw6v-h7f6 lists affected ranges: npm @hono/node-server >=0 <1.19.10 (fixed))
- Verified: https://github.com/advisories/GHSA-wc8c-qw6v-h7f6 (GitHub-reviewed advisory GHSA-wc8c-qw6v-h7f6 lists affected ranges: npm @hono/node-server >=0 <1.19.10)

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