Flight: HTTP method override enabled by default, facilitating CSRF escalation and middleware bypass

Exploitation

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

CVSS

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

EPSS

• CVE-2026-42551: 0.35% estimated exploitation activity in the next 30 days; percentile 28.79 (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 Request::getMethod() unconditionally honors the X-HTTP-Method-Override header and the $REQUEST['method'] parameter on any HTTP verb (including safe verbs such as GET), with no opt-in and no whitelist of permitted target methods. A GET request can silently become a DELETE or PUT, enabling CSRF escalation against destructive endpoints, bypass of middleware gated on unsafe verbs, and cache poisoning between CDN and origin. Affected code flight/net/Request.php (≈ lines 281-292): $REQUEST aggregates $GET and $POST; on PHP runtimes with requestorder=GPC it also includes $COOKIE. Proof of concept is dispatched as DELETE /item/42. is also dispatched as DELETE /item/42. Trivial CSRF vector (no JavaScript required): loaded on any attacker-controlled page triggers the destructive DELETE on page load, bypassing Same-Origin Policy (image loads are not blocked). Reproduced against /poc4/item/42. Impact - GET → DELETE / PUT CSRF on any route registered for unsafe verbs. - Bypass of…

Published by the source

6 May 2026, 21:38 UTC

Last modified by the source

14 May 2026, 20:40 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vxrr-w42w-w76g

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# Patch Next advisory brief: CVE-2026-42551

Advisory: Flight: HTTP method override enabled by default, facilitating CSRF escalation and middleware bypass
IDs: CVE-2026-42551, GHSA-vxrr-w42w-w76g
Record: https://patchnext.com/advisories/cve-2026-42551 (revision 1, source checked 26 Oct 2026, 14:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: flightphp/core 3.18.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist flightphp/core: affected < 3.18.1; fixed in 3.18.1

## Suggested inspection (read-only)
- Packagist flightphp/core: check the installed version with your package manager.

## 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 flightphp/core.
- 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://github.com/advisories/GHSA-vxrr-w42w-w76g (GitHub-reviewed advisory GHSA-vxrr-w42w-w76g lists affected ranges: Packagist flightphp/core >=0 <3.18.1)

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