Next.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a rewrites() or redirects() rule that builds its external destination hostname from request-controlled input can be pointed at an arbitrary hostname, regardless of the rule's hostname suffix. For a rewrite, Next.js proxies the request to that arbitrary host and serves the response from the application's origin, leading to Server-Side Request forgery. A redirects() rule configured this way is vulnerable to an Open Redirect. This issue has been fixed in versions 15.5.21 and 16.2.11.

Source published

27 Jul 2026 17:37:07 UTC

Source modified

28 Jul 2026 14:02:21 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/SI:L/SA:N

Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a rewrites() or redirects() rule that builds its external destination hostname from request-controlled input can be pointed at an arbitrary hostname, regardless of the rule's hostname suffix. For a rewrite, Next.js proxies the request to that arbitrary host and serves the response from the application's origin, leading to Server-Side Request forgery. A redirects() rule configured this way is vulnerable to an Open Redirect. This issue has been fixed in versions 15.5.21 and 16.2.11.

Source published

27 Jul 2026 18:16:59 UTC

Source modified

24 Oct 2026 13:10:00 UTC

Observed here

25 Oct 2026 15:18:45 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/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

CVSS 3.1 · [email protected] · Primary · 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

## Impact A `rewrites()` or `redirects()` rule that builds its external destination hostname from request-controlled input can be pointed at an arbitrary hostname, regardless of the rule's hostname suffix. For a rewrite, Next.js proxies the request to that arbitrary host and serves the response from the application's origin, leading to Server-Side Request forgery. A `redirects()` rule configured this way is vulnerable to an Open Redirect. This affects any destination that puts a dynamic segment in the hostname, whether from the path: ```javascript // next.config.js module.exports = { async rewrites() { return [ { source: '/:tenant', destination: 'https://:tenant.api.example.com', }, ] }, } ``` or from a `has` capture: ```javascript // next.config.js module.exports = { async rewrites() { return [ { source: '/', has: [{ type: 'query', key: 'region', value: '(?<region>.+)' }], destination: 'https://:region.api.example.com', }, ] }, } ``` ## Workarounds If you cannot upgrade immediately, do not build the hostname of an external `rewrites()` or `redirects()` destination from user-controlled input. If a dynamic subdomain is required, constrain the value to hostname-safe characters: `value: '(?<region>[a-z0-9-]+)'`.

Source published

22 Jul 2026 23:02:23 UTC

Source modified

10 Sep 2026 03:51:11 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/SI:L/SA:N

Publisher rating · HIGH