CVE-2026-12281
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 Shibboleth WordPress plugin before 2.5.4 does not fail closed when its HTTP header identity mode is enabled without an anti-spoofing key, treating any request that carries identity headers as an authenticated session without verifying them. On a deployment where untrusted client headers reach the application, an unauthenticated attacker can log in with forged identity headers and, when automatic account creation and the default administrator role mapping are enabled, create and sign in as a new administrator. Exploitation requires the non-default HTTP header attribute mode, an empty or absent spoof key, automatic account creation enabled, and a deployment that does not strip untrusted client headers before they reach the application.
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 Shibboleth WordPress plugin before 2.5.4 fails open when HTTP header identity mode is enabled without an anti-spoofing key configured. The plugin accepts any identity headers from incoming requests as valid authentication without verification, allowing unauthenticated attackers to forge headers and authenticate as arbitrary users, including administrators when automatic account creation with admin role mapping is enabled.
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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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 if the Shibboleth plugin is installedIn WordPress admin, go to Plugins > Installed Plugins and look for 'Shibboleth' or 'Shibboleth WP' plugin. Note the installed version number.Affected if Plugin is installed with a version before 2.5.4 (e.g., 2.5.3, 2.5.0, 1.x)
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Verify HTTP header identity mode is enabledCheck the plugin settings page for an option like 'HTTP Header Identity Mode', 'Enable Header Authentication', or similar. This is typically found under Settings > Shibboleth or a dedicated Shibboleth settings page in the WordPress admin.Affected if HTTP header identity mode is turned ON or enabled in the plugin configuration
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Confirm anti-spoofing key is missing or emptyLocate the 'Anti-Spoofing Key', 'Shared Secret Key', or 'Identity Verification Key' field in the Shibboleth plugin settings. Inspect whether this field is blank, empty, or not configured.Affected if The anti-spoofing key field is empty, blank, or has no value configured
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Check for automatic account creation with admin role mappingLook for settings related to 'Automatic Account Creation', 'Auto-provisioning', or 'User Role Mapping' in the plugin configuration. Determine if new users can be created automatically and if any role mapping assigns the Administrator role.Affected if Automatic user creation is enabled and maps to Administrator role (this increases exploit impact but is not required for the flaw to exist)
A user is affected if they have the Shibboleth plugin installed with version before 2.5.4 AND have HTTP header identity mode enabled AND lack a configured anti-spoofing key, regardless of whether automatic account creation is on.
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.
From vendor dataEnable and configure a non-empty anti-spoofing key in the plugin settings, disable automatic account creation if not required, and ensure upstream proxies or load balancers strip untrusted client-supplied identity headers before they reach the application.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-12281 — 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-2026-12281 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