{"id":"CVE-2026-59730","aliases":["EUVD-2026-49586","GHSA-r557-wffq-wvrc"],"status":"published","title":"@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect","description":"Astro is a web framework for content-driven websites. In versions 8.1.0 through 11.0.1, when trailingSlash: 'always' is 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 for exploitation: trailingSlash: 'always' must be set (non-default; the default is 'ignore'), the request path must not have a file extension in its final segment, and an attacker must deliver the crafted link to a user. This issue has been fixed in version 11.0.2.","severity":{"version":"4.0","score":2.1,"vector":"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","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.0046,"percentile":0.40395,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-601"],"published":"2026-07-20T23:22:22Z","modified":"2026-10-28T02:31:09Z","fixes":[{"ecosystem":"npm","package":"@astrojs/node","fixed_in":["11.0.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@astrojs/node","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.1.0"},{"fixed":"11.0.2"}]}]},{"source":"osv","ecosystem":"npm","package":"@astrojs/node","ranges":[{"type":"SEMVER","events":[{"introduced":"8.1.0"},{"fixed":"11.0.2"}]}]}],"products":[{"vendor":"withastro","product":"astro"}],"references":[{"url":"https://github.com/withastro/astro/security/advisories/GHSA-r557-wffq-wvrc","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/withastro/astro/pull/17252","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/withastro/astro/commit/eb6f97e391ee587747e37609c255c7cd4b9cce3c","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/withastro/astro/releases/tag/@astrojs/node@11.0.2","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59730","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-r557-wffq-wvrc"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59730.json","tags":["advisory"]},{"url":"https://github.com/withastro/astro","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-59730","title":"@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect","description":"Astro is a web framework for content-driven websites. In versions 8.1.0 through 11.0.1, when trailingSlash: 'always' is 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 for exploitation: trailingSlash: 'always' must be set (non-default; the default is 'ignore'), the request path must not have a file extension in its final segment, and an attacker must deliver the crafted link to a user. This issue has been fixed in version 11.0.2.","status":"published","published":"2026-07-27T20:00:28.662Z","modified":"2026-07-28T13:49:13.73Z","cvss":[{"version":"4.0","score":2.1,"vector":"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","level":"low","assessor":"cna"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:19:58.560602Z"}],"euvd":[{"id":"EUVD-2026-49586","description":"Astro is a web framework for content-driven websites. In versions 8.1.0 through 11.0.1, when trailingSlash: 'always' is 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 for exploitation: trailingSlash: 'always' must be set (non-default; the default is 'ignore'), the request path must not have a file extension in its final segment, and an attacker must deliver the crafted link to a user. This issue has been fixed in version 11.0.2.","status":"published","published":"2026-07-27T20:00:28Z","modified":"2026-07-28T13:49:13Z","cvss":[{"version":"4.0","score":2.1,"vector":"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","level":"low"}],"updated_at":"2026-11-02T18:02:31.827348Z"}],"ghsa":[{"id":"GHSA-r557-wffq-wvrc","title":"@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect","description":"### Impact\n\nWith `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.\n\n**Preconditions:**\n- `trailingSlash: 'always'` must be set (non-default; the default is `'ignore'`)\n- The request path must not have a file extension in its final segment\n- An attacker must deliver the crafted link to a user\n\n### Patches\n\nFixed by treating backslash-prefixed paths the same as `//`-prefixed paths in `isInternalPath()`, so they are no longer rewritten with a trailing slash.\n\n### Workarounds\n\nUse the default `trailingSlash: 'ignore'` setting, which does not issue trailing-slash redirects in the static file handler.\n\n### References\n\n- [WHATWG URL spec: backslash normalization](https://url.spec.whatwg.org/#url-parsing)","status":"published","published":"2026-07-20T23:22:22Z","modified":"2026-08-12T20:37:35Z","cvss":[{"version":"4.0","score":2.1,"vector":"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","level":"low"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:41:00.097339Z"}],"nvd":[{"id":"CVE-2026-59730","description":"Astro is a web framework for content-driven websites. In versions 8.1.0 through 11.0.1, when trailingSlash: 'always' is 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 for exploitation: trailingSlash: 'always' must be set (non-default; the default is 'ignore'), the request path must not have a file extension in its final segment, and an attacker must deliver the crafted link to a user. This issue has been fixed in version 11.0.2.","status":"published","published":"2026-07-27T21:17:05.843Z","modified":"2026-10-24T13:10:00.147Z","cvss":[{"version":"4.0","score":2.1,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"low","assessor":"secondary"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:12:33.249634Z"}],"osv":[{"id":"CVE-2026-59730","title":"@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect","description":"Astro is a web framework for content-driven websites. In versions 8.1.0 through 11.0.1, when trailingSlash: 'always' is 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 for exploitation: trailingSlash: 'always' must be set (non-default; the default is 'ignore'), the request path must not have a file extension in its final segment, and an attacker must deliver the crafted link to a user. This issue has been fixed in version 11.0.2.","status":"published","published":"2026-07-27T20:00:28.662Z","modified":"2026-10-28T02:31:09.133206488Z","cvss":[{"version":"4.0","score":2.1,"vector":"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","level":"low"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:45:12.496548Z"},{"id":"GHSA-r557-wffq-wvrc","title":"@astrojs/node: Backslash-prefixed paths not recognized as internal by trailing-slash redirect","description":"### Impact\n\nWith `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.\n\n**Preconditions:**\n- `trailingSlash: 'always'` must be set (non-default; the default is `'ignore'`)\n- The request path must not have a file extension in its final segment\n- An attacker must deliver the crafted link to a user\n\n### Patches\n\nFixed by treating backslash-prefixed paths the same as `//`-prefixed paths in `isInternalPath()`, so they are no longer rewritten with a trailing slash.\n\n### Workarounds\n\nUse the default `trailingSlash: 'ignore'` setting, which does not issue trailing-slash redirects in the static file handler.\n\n### References\n\n- [WHATWG URL spec: backslash normalization](https://url.spec.whatwg.org/#url-parsing)","status":"published","published":"2026-07-20T23:22:22Z","modified":"2026-08-12T20:45:07.791392853Z","cvss":[{"version":"4.0","score":2.1,"vector":"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","level":"low"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:46:55.480549Z"}]}}