CVE-2026-59730
@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect
Description
### Impact With `trailingSlash: 'always'` configured, the `@astrojs/node` standalone server's static file handler appends a trailing slash to request paths and issues a `301` redirect. Paths beginning with `/\` (slash-backslash) were not recognized as internal paths, so the handler would echo the raw path back in the `Location` header. Because browsers treat `\` as `/` per the WHATWG URL specification, the resulting redirect could resolve to an external host. **Preconditions:** - `trailingSlash: 'always'` must be set (non-default; the default is `'ignore'`) - The request path must not have a file extension in its final segment - An attacker must deliver the crafted link to a user ### Patches Fixed by treating backslash-prefixed paths the same as `//`-prefixed paths in `isInternalPath()`, so they are no longer rewritten with a trailing slash. ### Workarounds Use the default `trailingSlash: 'ignore'` setting, which does not issue trailing-slash redirects in the static file handler. ### References - [WHATWG URL spec: backslash normalization](https://url.spec.whatwg.org/#url-parsing)
How to fix CVE-2026-59730
To remediate CVE-2026-59730, upgrade the affected package to a fixed version below.
- —upgrade to 11.0.2 or later
Is CVE-2026-59730 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-59730.
Affected packages (1)
- >= 8.1.0, < 11.0.2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N |