Answer in brief
CVE-2026-54286 records a Medium severity (CVSS 5.9) path traversal vulnerability in hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`). The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
Answer in brief
CVE-2026-54286 records a Medium severity (CVSS 5.9) path traversal vulnerability in hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`). The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
Update hono to 4.12.25 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanPath Traversal describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-54286 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| hononpm | <4.12.25 | 4.12.25 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
### Summary 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. Directory escape (`..`) remains blocked. ### Details The router splits paths only on `/`, so `/admin%5Csecret.txt` is one segment and middleware on `/admin/*` does not run. The `serve-static` guard rejects `.`/`..` and consecutive separators but lets a lone `\` through; on Windows the file resolver re-splits it into the protected subtree. This affects Windows hosts serving static files via the Node, Bun, or Deno adapters that guard a static subtree with prefix-mounted middleware. ### Impact An unauthenticated attacker can read static files under a middleware-guarded prefix on Windows hosts. The read stays within the configured root; escape outside the root is not possible.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-54286 records a Medium severity (CVSS 5.9) path traversal vulnerability in hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`). The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for hono.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate hono to 4.12.25 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanPath Traversal describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-54286 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| hononpm | <4.12.25 | 4.12.25 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
### Summary 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. Directory escape (`..`) remains blocked. ### Details The router splits paths only on `/`, so `/admin%5Csecret.txt` is one segment and middleware on `/admin/*` does not run. The `serve-static` guard rejects `.`/`..` and consecutive separators but lets a lone `\` through; on Windows the file resolver re-splits it into the protected subtree. This affects Windows hosts serving static files via the Node, Bun, or Deno adapters that guard a static subtree with prefix-mounted middleware. ### Impact An unauthenticated attacker can read static files under a middleware-guarded prefix on Windows hosts. The read stays within the configured root; escape outside the root is not possible.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-54286 records a Medium severity (CVSS 5.9) path traversal vulnerability in hono: Path traversal in `serve-static` on Windows via encoded backslash (`%5C`). The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for hono.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard