{"id":"GHSA-9phm-9p8f-hw5m","summary":"Nitro has an Open Redirect via Protocol-Relative URL Bypass in Wildcard Route Rules","details":"A redirect route rule like:\n\n```ts\nrouteRules: {\n  \"/legacy/**\": { redirect: \"/**\" }\n}\n```\n\nis intended to rewrite paths within the same host. Before the patch, an attacker could turn the rewrite into a cross-host redirect by sliding an extra slash in after the rule prefix. Example exploit:\n\n```\nGET /legacy//evil.com\n```\n\nNitro stripped `/legacy` from the matched pathname and joined the remainder against the rule's target. The remainder was `//evil.com`, which the join preserved verbatim, so Nitro responded with `Location: //evil.com`. Browsers resolve `//evil.com` as a protocol-relative URL against the current scheme, sending the user to `https://evil.com`. \n\n### Are you affected?\n\nUsers may be affected if **all** of the following are true:\n\n1. Their project uses Nitro's `routeRules` with a `redirect` entry.\n2. The target uses a `/**` wildcard suffix to forward sub-paths (e.g. `redirect: \"/**\"`, `redirect: \"/new/**\"`, `proxy: { to: \"http://upstream/**\" }`).\n3. The `redirect` rule is _not_ handled natively at the CDN layer. The `vercel`, `netlify`, `cloudflare-pages`, and `edgeone` presets translate `routeRules.redirect` into platform config (`vercel.json`, `_redirects`, EdgeOne v3 config) and serve the redirect at the edge — those deployments bypass the Nitro runtime entirely and are not affected. Every other preset executes the redirect through the Nitro runtime and can be vulnerable.\n\n## Impact\n\nOpen redirect from any host serving Nitro with a wildcard `redirect` rule. The redirect target is fully attacker-controlled, the URL looks legitimate (it starts with the victim's domain), and the browser silently follows it.\n\n## Patched versions\n\nUpgrade to one of:\n\n- [2.13.4](https://github.com/nitrojs/nitro/releases/tag/v2.13.4) or later (or upgrade lockfile with latest ufo 1.6.4+)\n- [3.0.260429-beta](https://github.com/nitrojs/nitro/releases/tag/v3.0.260429-beta) or later (https://github.com/nitrojs/nitro/pull/4236)\n\nThe fix has two parts:\n\n1. `ufo` is bumped to `^1.6.4` ([unjs/ufo@5cd9e67](https://github.com/unjs/ufo/commit/5cd9e676711af3f4e4b5398ddf6ca8d52c1c7e1f)), which collapses any run of leading slashes to a single `/` inside `withoutBase`. This covers the typical `\"/scope/**\"` rule.\n2. The Nitro runtime additionally collapses leading `//` before joining when the rule path itself is `/**` (in rare case which case `withoutBase` is never called and the raw pathname flows straight into `joinURL(\"\", …)`).","aliases":["CVE-2026-44372"],"modified":"2026-06-09T02:15:07.684570522Z","published":"2026-05-06T23:02:45Z","database_specific":{"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-05-06T23:02:45Z","nvd_published_at":"2026-05-13T21:16:47Z","cwe_ids":["CWE-601"]},"references":[{"type":"WEB","url":"https://github.com/nitrojs/nitro/security/advisories/GHSA-9phm-9p8f-hw5m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44372"},{"type":"WEB","url":"https://github.com/nitrojs/nitro/pull/4236"},{"type":"WEB","url":"https://github.com/unjs/ufo/commit/5cd9e676711af3f4e4b5398ddf6ca8d52c1c7e1f"},{"type":"PACKAGE","url":"https://github.com/nitrojs/nitro"},{"type":"WEB","url":"https://github.com/nitrojs/nitro/releases/tag/v2.13.4"},{"type":"WEB","url":"https://github.com/nitrojs/nitro/releases/tag/v3.0.260429-beta"}],"affected":[{"package":{"name":"nitro","ecosystem":"npm","purl":"pkg:npm/nitro"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.0.260429-beta"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-9phm-9p8f-hw5m/GHSA-9phm-9p8f-hw5m.json"}},{"package":{"name":"nitropack","ecosystem":"npm","purl":"pkg:npm/nitropack"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.13.4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-9phm-9p8f-hw5m/GHSA-9phm-9p8f-hw5m.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"}]}