CVE-2026-73423

Astro is a web framework for content-driven websites. From 7.0.0 until 7.0.6, the composable astro/hono pipeline installs security.checkOrigin only through the middleware() primitive, while actions() and pages() can dispatch to user code independently. Mounting actions() before middleware(), as in the examples/advanced-routing example and Cloudflare Hono documentation, allows cross-origin form-encoded action requests to execute before the origin check, and using pages() without middleware() drops the check for on-demand endpoints and pages. The flaw enables blind write-only cross-site request forgery using the victim's cookies against ActionHandler.handle and PagesHandler.handleWithErrorFallback when manifest.checkOrigin is enabled; the attacker can trigger a state-mutating action or endpoint handler but cannot read the cross-origin response. The default non-composable astro() pipeline is not affected. This issue is fixed in version 7.0.6.

Astro is a web framework for content-driven websites. From 7.0.0 until 7.0.6, the composable astro/hono pipeline installs security.checkOrigin only through the middleware() primitive, while actions() and pages() can dispatch to user code independently. Mounting actions() before middleware(), as in the examples/advanced-routing example and Cloudflare Hono documentation, allows cross-origin form-encoded action requests to execute before the origin check, and using pages() without middleware() drops the check for on-demand endpoints and pages. The flaw enables blind write-only cross-site request forgery using the victim's cookies against ActionHandler.handle and PagesHandler.handleWithErrorFallback when manifest.checkOrigin is enabled; the attacker can trigger a state-mutating action or endpoint handler but cannot read the cross-origin response. The default non-composable astro() pipeline is not affected. This issue is fixed in version 7.0.6.

Summary

In the composable astro/hono pipeline, the security.checkOrigin protection is only installed by the middleware() primitive. The actions() and pages() primitives each dispatch to user code independently, so a pipeline that mounts either primitive before (or without) middleware() will bypass the origin check for those requests.

Details

security.checkOrigin (default: true) is intended to reject cross-site POST/PUT/PATCH/DELETE form submissions. In the classic pipeline (astro() all-in-one), the check always runs because Astro injects a virtual middleware module even when the user has no src/middleware.ts. In the composable astro/hono pipeline, the user assembles primitives manually. The check is only installed inside middleware() — so:

• Mounting actions() before middleware() allows cross-origin form-encoded action requests to execute before the gate runs. The examples/advanced-routing example and the Cloudflare hono docs shipped this order.
• Omitting middleware() entirely (reasonable for apps with no custom middleware) silently drops checkOrigin protection for all on-demand endpoints and pages dispatched through pages().

The attack is a blind write-only CSRF: the attacker can trigger a state-mutating action or endpoint handler using the victim's cookies, but cannot read the cross-origin response body.

Affected versions

Astro >= 7.0.0 when using the composable astro/hono pipeline with either:

• actions() mounted before middleware(), or
• pages() used without middleware()

The default (non-composable) pipeline is not affected.

Fix

The origin check is now applied at each dispatch sink (ActionHandler.handle and PagesHandler.handleWithErrorFallback), gated on manifest.checkOrigin, using the same predicate as the middleware. The check is order-independent and a no-op when middleware() has already run.

Fix: https://github.com/withastro/astro/pull/17250

Workaround

Ensure middleware() is mounted before both actions() and pages() in the composable pipeline, and that it is always included even when no custom middleware logic is needed:

app.use(middleware());
app.use(actions());
app.use(pages());

Astro is a web framework for content-driven websites. From 7.0.0 until 7.0.6, the composable astro/hono pipeline installs security.checkOrigin only through the middleware() primitive, while actions() and pages() can dispatch to user code independently. Mounting actions() before middleware(), as in the examples/advanced-routing example and Cloudflare Hono documentation, allows cross-origin form-encoded action requests to execute before the origin check, and using pages() without middleware() drops the check for on-demand endpoints and pages. The flaw enables blind write-only cross-site request forgery using the victim's cookies against ActionHandler.handle and PagesHandler.handleWithErrorFallback when manifest.checkOrigin is enabled; the attacker can trigger a state-mutating action or endpoint handler but cannot read the cross-origin response. The default non-composable astro() pipeline is not affected. This issue is fixed in version 7.0.6.

Astro is a web framework for content-driven websites. From 7.0.0 until 7.0.6, the composable astro/hono pipeline installs security.checkOrigin only through the middleware() primitive, while actions() and pages() can dispatch to user code independently. Mounting actions() before middleware(), as in the examples/advanced-routing example and Cloudflare Hono documentation, allows cross-origin form-encoded action requests to execute before the origin check, and using pages() without middleware() drops the check for on-demand endpoints and pages. The flaw enables blind write-only cross-site request forgery using the victim's cookies against ActionHandler.handle and PagesHandler.handleWithErrorFallback when manifest.checkOrigin is enabled; the attacker can trigger a state-mutating action or endpoint handler but cannot read the cross-origin response. The default non-composable astro() pipeline is not affected. This issue is fixed in version 7.0.6.

Summary

In the composable astro/hono pipeline, the security.checkOrigin protection is only installed by the middleware() primitive. The actions() and pages() primitives each dispatch to user code independently, so a pipeline that mounts either primitive before (or without) middleware() will bypass the origin check for those requests.

Details

security.checkOrigin (default: true) is intended to reject cross-site POST/PUT/PATCH/DELETE form submissions. In the classic pipeline (astro() all-in-one), the check always runs because Astro injects a virtual middleware module even when the user has no src/middleware.ts. In the composable astro/hono pipeline, the user assembles primitives manually. The check is only installed inside middleware() — so:

• Mounting actions() before middleware() allows cross-origin form-encoded action requests to execute before the gate runs. The examples/advanced-routing example and the Cloudflare hono docs shipped this order.
• Omitting middleware() entirely (reasonable for apps with no custom middleware) silently drops checkOrigin protection for all on-demand endpoints and pages dispatched through pages().

The attack is a blind write-only CSRF: the attacker can trigger a state-mutating action or endpoint handler using the victim's cookies, but cannot read the cross-origin response body.

Affected versions

Astro >= 7.0.0 when using the composable astro/hono pipeline with either:

• actions() mounted before middleware(), or
• pages() used without middleware()

The default (non-composable) pipeline is not affected.

Fix

The origin check is now applied at each dispatch sink (ActionHandler.handle and PagesHandler.handleWithErrorFallback), gated on manifest.checkOrigin, using the same predicate as the middleware. The check is order-independent and a no-op when middleware() has already run.

Fix: https://github.com/withastro/astro/pull/17250

Workaround

Ensure middleware() is mounted before both actions() and pages() in the composable pipeline, and that it is always included even when no custom middleware logic is needed:

app.use(middleware());
app.use(actions());
app.use(pages());