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Cross-Site Request Forgery (CSRF)Weakness · CWE-352

CVE-2026-8905

MEDIUM · 6.1 CVSS v3.1 Published 2026-06-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges 8 weeks old

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 · unedited
The Osiris Signature Banner plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 0.5. This is due to missing or incorrect nonce validation on a function. This makes it possible for unauthenticated attackers to update settings and inject malicious web scripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

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 confidence

The Osiris Signature Banner WordPress plugin lacks proper nonce validation on a settings function, allowing unauthenticated attackers to forge administrative requests. This CSRF vulnerability enables attackers to modify plugin settings and inject malicious web scripts, as the application cannot verify the request originated from an legitimate admin session.

MitigationUpdate to a patched version once released; in the meantime, implement nonce verification on all settings-related functions in the plugin to validate request authenticity.

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
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify plugin installation
    In WordPress admin, go to Plugins > Installed Plugins and look for 'Osiris Signature Banner' or check the /wp-content/plugins/ directory for an osiris-signature-banner folder. Note the installed version from the plugin metadata.
    Affected if The plugin is installed and active in WordPress
  2. Check plugin version
    Locate the plugin's main PHP file (usually osiris-signature-banner.php) and find the Version header in the plugin comment block. Compare this version to any known patched version from the plugin changelog or security advisory.
    Affected if The installed version lacks the security patch for nonce validation (version comparison required)
  3. Identify settings function presence
    In the plugin directory, locate files that handle plugin settings (often in includes/ folder or main plugin file). Look for functions that update options using update_option() or similar WordPress settings functions.
    Affected if The plugin has a settings/options function that modifies plugin configuration
  4. Inspect for nonce validation
    In the identified settings-related PHP files, search for 'wp_nonce_field', 'check_admin_referer', 'wp_verify_nonce', or 'nonce' in the function that processes settings updates. Verify that a valid nonce is passed and verified before any settings modification occurs.
    Affected if The settings function lacks proper nonce verification (nonce field missing or not validated before processing)
  5. Test settings submission CSRF vulnerability
    From a non-authenticated browser, attempt to submit a crafted settings POST request to wp-admin/admin-post.php or the plugin's settings handler endpoint without a valid nonce token. If the request processes without rejection, the vulnerability is present.
    Affected if Settings can be modified without a valid authenticated nonce token

You are affected if the Osiris Signature Banner plugin is installed AND its settings function processes requests without properly validating a nonce token, allowing forged administrative requests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update to a patched version once released; in the meantime, implement nonce verification on all settings-related functions in the plugin to validate request authenticity.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8905 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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