Astro's X-Forwarded-Host is reflected without validation

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS

• CVE-2025-61925: 0.41% estimated exploitation activity in the next 30 days; percentile 35.12 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When running Astro in on-demand rendering mode using a adapter such as the node adapter it is possible to maliciously send an X-Forwarded-Host header that is reflected when using the recommended Astro.url property as there is no validation that the value is safe. Details Astro reflects the value in X-Forwarded-Host in output when using Astro.url without any validation. It is common for web servers such as nginx to route requests via the Host header, and forward on other request headers. As such as malicious request can be sent with both a Host header and an X-Forwarded-Host header where the values do not match and the X-Forwarded-Host header is malicious. Astro will then return the malicious value. This could result in any usages of the Astro.url value in code being manipulated by a request. For example if a user follows guidance and uses Astro.url for a canonical link the canonical link can be manipulated to another site. It is not impossible to imagine that the value could…

Published by the source

10 Oct 2025, 23:41 UTC

Last modified by the source

11 Oct 2025, 00:12 UTC

Source last checked

26 Oct 2026, 12:38 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5ff5-9fcw-vg88

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5ff5-9fcw-vg88

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# Patch Next advisory brief: CVE-2025-61925

Advisory: Astro's `X-Forwarded-Host` is reflected without validation
IDs: CVE-2025-61925, GHSA-5ff5-9fcw-vg88
Record: https://patchnext.com/advisories/cve-2025-61925 (revision 2, source checked 26 Oct 2026, 12:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: astro 5.14.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm astro: affected < 5.14.3; fixed in 5.14.3

## Suggested inspection (read-only)
- `npm ls astro --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on astro.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5ff5-9fcw-vg88 (OSV record GHSA-5ff5-9fcw-vg88 lists affected ranges: npm astro >=0 <5.14.3 (fixed))
- Verified: https://github.com/advisories/GHSA-5ff5-9fcw-vg88 (GitHub-reviewed advisory GHSA-5ff5-9fcw-vg88 lists affected ranges: npm astro >=0 <5.14.3)

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