CVE-2026-31889

We identified and fixed a vulnerability in the Shopware app registration flow that could, under specific conditions, allow attackers to take over the communication channel between a shop and an app. By abusing app re‑registration, an attacker could redirect app traffic to an attacker‑controlled domain and potentially obtain API credentials intended for the legitimate shop.
We have no evidence that this vulnerability has been exploited.

Affected Scope

• All apps (public and private) that use a registrationUrl in their app manifest and rely on the legacy HMAC‑based registration flow.
• Both on‑premise and cloud installations are affected until updated to a fixed Shopware version or protected by the latest Shopware Security Plugin.
• Shopware services and first‑party apps using the affected SDKs were reviewed and patched.
  The vulnerability does not affect core storefront or administration authentication; it is limited to the app system’s registration and re‑registration mechanism.

Root Cause

The legacy app registration flow used HMAC‑based authentication without sufficiently binding a shop installation to its original domain. During re‑registration, the shop-url could be updated without proving control over the previously registered shop or domain. This made targeted hijacking of app communication feasible if an attacker possessed the relevant app‑side secret.

Required Action

For Merchants / Shop Operators

1. Update Shopware
   • Upgrade to the latest Shopware 6.6.x / 6.7.x release that includes this fix, or
   • Install/update the latest Shopware Security Plugin version providing the hotfix for your Shopware 6 installation.
2. Update apps
   • Ensure all installed apps are updated to the latest versions provided by their manufacturers.
   • If you suspect compromised keys or observe unexpected app behaviour, re‑install the affected app or trigger key rotation as documented by the app vendor.

For App Manufacturers / Partners

1. Update SDKs / implementations
   • Update to the latest Shopware app SDKs (PHP / JS) or apply the documented changes if you maintain a custom implementation of the registration flow.
   • Validate both shopware-app-signature and shopware-shop-signature for re‑registration requests.
   • Always generate and store a new shop secret on re‑registration and only switch to it after a successful confirmation.
2. Review your apps
   • Verify that your app does not blindly accept changed shop-url values without validating signatures.
   • Check any logic that exposes data or functionality based solely on HMAC signatures from shops and ensure it aligns with the hardened registration model.
3. Test your implementation
   • Use the updated tooling and guidance provided in your Shopware Account / partner channels to validate that your registration flow complies with the new requirements.

In a successful attack, an attacker who already knows certain app‑side secrets could:

• Re‑register an existing app installation with a domain under their control.
• Intercept App → Shop communication and cause data tampering (“data poisoning”).
• Obtain API integration credentials of the shop with the permissions granted to the app.
  Shop owners and app manufacturers would typically observe this as “app malfunction” rather than an obvious security issue, which increases the need for hardening.

CVE-2026-31889 has a CVSS score of 8.9 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.7.8.1, 6.6.10.15); upgrading removes the vulnerable code path.

Kodem intelligence

We have hardened the app registration and re‑registration process:

• Dual signature requirement: Re‑registration now requires both the app secret and the existing shop secret to be presented and validated.
• Mandatory secret rotation: On successful re‑registration, a new shop secret is generated and verified; the previous secret is invalidated after a short grace period.
• Stricter validation: Shopware only accepts updated shop URLs and secrets once the full confirmation flow has completed successfully.
• Improved logging and monitoring: All re‑registrations are now logged with additional metadata to help detect abuse patterns.
  These changes are delivered via:
• Updated Shopware core releases (6.6.x, 6.7.x), and
• Updated versions of the Shopware Security Plugin for supported older versions,
• Updated official SDKs (e.g. PHP and JavaScript app SDKs).

1. What is CVE-2026-31889? CVE-2026-31889 is a high-severity security vulnerability in shopware/platform (composer), affecting versions >= 6.7.0.0, < 6.7.8.1. It is fixed in 6.7.8.1, 6.6.10.15.
2. How severe is CVE-2026-31889? CVE-2026-31889 has a CVSS score of 8.9 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-31889?
   • shopware/platform (composer) (versions >= 6.7.0.0, < 6.7.8.1)
   • shopware/core (composer) (versions >= 6.7.0.0, < 6.7.8.1)
4. Is there a fix for CVE-2026-31889? Yes. CVE-2026-31889 is fixed in 6.7.8.1, 6.6.10.15. Upgrade to this version or later.
5. Is CVE-2026-31889 exploitable, and should I be worried? Whether CVE-2026-31889 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-31889 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-31889?
   • Upgrade shopware/platform to 6.7.8.1 or later
   • Upgrade shopware/platform to 6.6.10.15 or later
   • Upgrade shopware/core to 6.7.8.1 or later
   • Upgrade shopware/core to 6.6.10.15 or later