CVE-2026-59730
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
⚡ Watch CVE-2026-59730
Get an email if CVE-2026-59730 is added to CISA KEV, gains public exploit code, or a new advisory cites it — max one per day, one-click unsubscribe.
Exploitation outlook
- Low exploitation risk0.36% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 29% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
Embed the live status
— this badge updates automatically when the KEV or exploit status changes. How to embed it →
[](https://www.csirts.com/cve/CVE-2026-59730)