CVE-2026-11855
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe Simple Membership WordPress plugin before 4.7.5 does not verify the authenticity of Stripe webhook requests when no signing secret is configured, nor escape a value taken from them before outputting it in an administrator notice, allowing unauthenticated attackers to inject arbitrary web scripts that execute in the context of a logged-in administrator.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Simple Membership WordPress plugin before 4.7.5 lacks proper validation of Stripe webhook requests when no signing secret is configured, allowing unauthenticated attackers to send arbitrary webhook data. Additionally, values extracted from these webhooks are not escaped before being output in administrator notices, resulting in stored XSS that executes in the context of a logged-in administrator session.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Simple Membership plugin versionIn WordPress admin, go to Plugins > Installed Plugins and look for 'Simple Membership' to see the version number, or inspect the main plugin file (simple-membership.php) and look for the 'Version' header commentAffected if The installed version is lower than 4.7.5
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Verify Stripe webhook signing secret is not configuredNavigate to the plugin settings (Simple Membership > Settings > Payment Settings > Stripe tab) and check if the 'Webhook Signing Secret' field is empty or not configuredAffected if The Stripe webhook signing secret is left empty, allowing unauthenticated webhook requests
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Confirm Stripe integration is enabledCheck if Stripe payment gateway is active in Simple Membership > Payment Settings > Payment MethodsAffected if Stripe is enabled as a payment method, making the webhook endpoint accessible to attackers
A user is affected if they run Simple Membership plugin versions before 4.7.5 AND have Stripe enabled without a configured webhook signing secret, as this allows unauthenticated webhook injection leading to stored XSS in admin notices.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpdate to plugin version 4.7.5 or later and configure a valid Stripe webhook signing secret to enable request authenticity verification.
Simple Membership plugin version 4.7.5 or later
- 1. Navigate to the WordPress admin dashboard
- 2. Go to Plugins > Installed Plugins
- 3. Locate the 'Simple Membership' plugin
- 4. If the plugin is outdated, click 'Update Now' to upgrade to version 4.7.5 or later
- 5. Alternatively, download the latest version from wordpress.org and upload via Plugins > Add New > Upload Plugin
- 6. After updating, verify the version number reflects 4.7.5 or higher
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-11855 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-11855 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data