Plugin Name	Ravelry Designs Widget
Type of Vulnerability	Cross-Site Scripting (XSS)
CVE Number	CVE-2026-1903
Urgency	Low
CVE Publish Date	2026-02-13
Source URL	CVE-2026-1903

Stored XSS in Ravelry Designs Widget (<=1.0.0): What happened, why it matters, and how WP-Firewall protects your site

Author: WP‑Firewall Security Research Team
Date: 2026-02-13

TL;DR — A stored Cross‑Site Scripting (XSS) vulnerability (CVE‑2026‑1903) was disclosed in the Ravelry Designs Widget WordPress plugin (versions <= 1.0.0). An authenticated user with Contributor privileges can inject malicious script via the sb_ravelry_designs shortcode “layout” attribute that is stored in post content and rendered to site visitors. Impact is limited by required privilege and user interaction, but exploitation can result in session theft, phishing, and site defacement. This post explains the technical root cause, impact scenarios, detection and hunting steps, immediate mitigations you can apply today, recommended WAF/virtual patching rules (for WP‑Firewall users), and developer fixes to permanently close the hole.

Table of contents

• Summary and affected versions
• Vulnerability technical analysis (root cause)
• Exploitation proof-of-concept (conceptual, sanitized)
• Real‑world impact and threat model
• Detection and hunting — how to find if you were hit
• Immediate mitigations for site owners (step‑by‑step)
• WP‑Firewall virtual patching and WAF rules (ready to apply)
• Developer remediation — secure code snippets and patterns
• Longer‑term hardening and operational recommendations
• Secure your site today with WP‑Firewall (Free plan details)
• Conclusion and references

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Summary and affected versions

• Software: Ravelry Designs Widget — WordPress plugin
• Affected versions: <= 1.0.0
• Vulnerability class: Stored Cross‑Site Scripting (Stored XSS)
• Vector: sb_ravelry_designs shortcode — layout attribute
• Required privilege: Contributor (authenticated)
• CVE: CVE‑2026‑1903
• CVSSv3 Base Score: 6.5 (User interaction required, limited by privilege)

A security researcher reported that the plugin allows an authenticated user with Contributor privileges to include unfiltered markup in the layout attribute of the sb_ravelry_designs shortcode. That data is stored in post content and later output without sufficient escaping/encoding, resulting in a stored XSS — meaning visitors (or admins) who view the post could have arbitrary script executed in their browsers.

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Vulnerability technical analysis (root cause)

Shortcodes in WordPress are a convenient way to embed dynamic widgets and markup inside post content. When a shortcode handler outputs markup it must treat any input coming from users (including shortcode attributes) as untrusted. The secure pattern is:

• Validate and sanitize inputs when accepting them.
• Escape outputs at render time according to the output context (HTML attribute, HTML body, JavaScript, URL, etc.).

In this case the plugin:

1. Registers a shortcode sb_ravelry_designs.
2. Accepts a layout attribute on that shortcode (likely to allow templates or layout choices).
3. Does not properly sanitize/validate the layout attribute supplied by the content author (Contributor).
4. Stores the post content (with the malicious shortcode attribute) in wp_posts.post_content.
5. When rendering the shortcode on the frontend, the plugin includes the layout attribute value inside markup/attributes without escaping (for example, echoing it into an HTML attribute or innerHTML context).
6. As a result, a value such as "></div><script>…</script> or onerror=... ends up executing in a visitor’s browser — a classic stored XSS.

Why a Contributor matters: Contributors can create and edit posts but cannot publish them. If the site auto-publishes or an editor/admin reviews and publishes the post, content becomes visible to visitors. On some sites contributor posts are published by editors — so a malicious contributor could trick an editor into publishing (social engineering) or the site may use a workflow that auto-publishes contributor content in certain contexts.

Key root cause summary: unsanitized/unescaped user-supplied attribute used in output context.

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Exploitation proof-of-concept (conceptual, sanitized)

Below is a concept-level PoC that demonstrates the pattern without providing a weaponized payload. The purpose is to help defenders and developers reproduce and test safely in controlled environments.

Assume a post editor allows the following shortcode in post content:

[sb_ravelry_designs layout="DEFAULT"]

A malicious contributor edits a draft and changes to:

[sb_ravelry_designs layout='"><script></script><sb']

If the plugin then renders this attribute into an element like:

<div class="ravelry-layout <?php echo $layout; ?>">...</div>

and $layout is printed without escaping, the injected <script> executes in the visitor’s browser.

Safe test steps for defenders (in staging only):

1. Create a staging site with the vulnerable plugin (if you must reproduce).
2. Create a contributor account (do not use production credentials).
3. Submit a post with a benign test value that includes clearly visible markers (e.g., layout="INJECTION_TEST_<b>1</b>").
4. Preview the post in a browser on the staging environment and inspect the HTML output to see how the attribute value is included.
5. If the raw value is present unescaped in an HTML attribute or innerHTML, the plugin is vulnerable.

DO NOT test exploits on production sites or on other people’s sites.

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Real‑world impact and threat model

Stored XSS is serious because malicious JavaScript runs in the security context of site visitors, allowing multiple malicious actions:

• Cookie/session theft (if cookies are not HttpOnly) and token exfiltration.
• Performing actions on behalf of logged-in visitors (CSRF amplification).
• Keylogging, credential harvesting (fake login overlays), or redirecting visitors to phishing or malware distribution pages.
• Injecting content that damages reputation (defacement, fake offers).
• Targeting privileged users (editors/admins) who view the page and thereby escalate to full‑site compromise (if admin privileges can be exploited via XSS).

However, this particular issue has mitigating factors:

• An attacker needs an account with Contributor privileges to inject payloads.
• Successful impact often requires the injected content to be published (if Contributors cannot publish, social engineering to trick editors might be necessary).
• Many sites have content moderation workflows reducing the chance of immediate public exposure.

Given CVSS 6.5 and these constraints, the vulnerability is medium risk in general — but it becomes high risk if contributor accounts are freely issued (for example, low-trust registrations) or robust moderation is absent.

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Detection and hunting — how to find if you were hit

If you run WordPress sites, check for indicators of compromise and look for suspicious shortcode parameters stored in the database.

1. Search post content for the vulnerable shortcode:
   • WP‑CLI:
     wp db query "SELECT ID, post_title, post_status FROM wp_posts WHERE post_content LIKE '%[sb_ravelry_designs%';"
   • SQL:
     SELECT ID, post_title, post_status FROM wp_posts WHERE post_content LIKE '%[sb_ravelry_designs%';
2. Search for suspicious characters/patterns in post_content:
   • Look for <script or onerror= or pattern breaks like ">< inside the shortcode:
     wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content REGEXP '\\[sb_ravelry_designs[^\\]]*layout=[^\\]]*(<|\\x22|\\x27|script|onerror)';"
3. Log analysis:
   • Review web server logs and WAF logs for requests containing sb_ravelry_designs combined with <, script, onerror, or suspicious encoded characters (%3C, %3E, %3D).
   • Look for odd POST or PUT requests from Contributor accounts.
4. Check user accounts:
   • List users with role Contributor and audit their activity timestamps and IPs.
     WP‑CLI: wp user list --role=contributor --fields=ID,user_login,user_email,user_registered
5. Browser console and page source:
   • If you suspect a particular post, open it in a non-admin browser and view source; scan for unescaped attribute values or unexpected <script> tags.
6. Alerts from security tools:
   • If you run a scanning solution or WAF, check for alerts referencing stored XSS or shortcode attribute patterns.

If you find a confirmed injection, take action immediately (see next section).

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Immediate mitigations for site owners (step‑by‑step)

These actions prioritize containment and reduce attack surface quickly. Follow this order:

1. Put the site in maintenance mode if public exposure is unacceptable.
2. Temporarily disable the plugin:
   • Dashboard: Plugins → Deactivate Ravelry Designs Widget.
   • WP‑CLI: wp plugin deactivate ravelry-designs-widget
3. If you cannot deactivate (e.g., business reasons), apply WAF rules (see WP‑Firewall rules below) to block attempts to render or serve content with suspicious layout attributes.
4. Audit post content:
   • Use the SQL/WP‑CLI queries above to find posts containing the shortcode.
   • For each post, inspect post_content. If you find suspicious attributes, either remove the shortcode or sanitize the attribute value in the content (replace with a safe default).
5. Revoke or restrict contributor accounts:
   • Temporarily set suspicious contributors to Subscriber or disable accounts until reviewed.
   • Force a password reset for Contributor accounts you cannot immediately audit.
6. Review and rotate secrets:
   • If you suspect admin sessions were compromised (e.g., admin viewed an infected page), rotate admin passwords and invalidate all active sessions (Plugins exist to force logout all users, or you can update wp_usermeta session tokens).
7. Scan and clean:
   • Run your site malware scanner (preferably from a staging copy) to enumerate injected scripts and remove them.
   • If you find server-side changes or new admin users, escalate to full incident response.
8. Notify:
   • If the site processes user data and you have a breach affecting personal data, follow your compliance and notification obligations.

These steps will reduce risk while you apply more permanent fixes.

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WP‑Firewall virtual patching and WAF rules (ready to apply)

WP‑Firewall users can protect vulnerable sites immediately by enabling virtual patching — blocking malicious payloads at the edge before they reach your application. Below are recommended rule strategies and sample rules. Apply in staging first.

Rule strategy summary:

• Block requests that attempt to save or publish posts with suspicious shortcode content (POST requests to /wp-admin/post.php /wp-admin/post-new.php /wp-json/wp/v2/posts).
• Block requests that include the sb_ravelry_designs shortcode with an attribute containing <, >, script, onerror, javascript: or broken quoting.
• Block requests that try to render content containing the vulnerable attribute pattern in output (GET requests retrieving posts that include suspicious attributes).

Important: Rules should minimize false positives by focusing on character sequences incompatible with legitimate attribute values (e.g., <, >, script, onerror, eval\().

Example WP‑Firewall rule (pseudocode / pattern based):

1. Block POSTs that include sb_ravelry_designs with a layout attribute containing < or >:
   • Condition: HTTP Method == POST
   • Request URI matches: /wp-admin/post.php OR /wp-json/wp/v2/posts
   • Request body matches regex:
     (?is)\[sb_ravelry_designs[^\]]*layout\s*=\s*(['"])[^'"]*(<|>|script|onerror|javascript:)[^'"]*\1

   Action: Block and log, return 403.

2. Block GETs serving posts if the rendered page contains unescaped patterns (edge mitigation for published exploit):
   • Condition: HTTP Method == GET
   • Response body matches regex:
     (?is)\[sb_ravelry_designs[^\]]*layout\s*=\s*(['"])[^'"]*(<|>|script|onerror|javascript:)[^'"]*\1
   • If the response contains a raw script tag coming from post content, apply content injection prevention: strip the attribute or return a sanitized copy.

   Action: Serve a sanitized or cached version or return 403 for known malicious content.

3. IP or user lockout for repeated attempts:
   • If the same IP triggers the above POST block 3 times within 10 minutes, auto-block for X minutes. Also notify the admin.

Sample ModSecurity-style rule (for sysadmins converting to server WAF):

SecRule REQUEST_METHOD "POST" "chain,deny,id:1001001,msg:'Block sb_ravelry_designs layout XSS attempt',log"
  SecRule REQUEST_URI "@pm /wp-admin/post.php /wp-json/wp/v2/posts /wp-admin/post-new.php" "chain"
  SecRule ARGS "@rx (?i)\[sb_ravelry_designs[^\]]*layout\s*=\s*(['\"])[^'\"]*(<|>|script|onerror|javascript:)[^'\"]*\1" "t:none,t:urlDecode"

Important notes:

• Use t:urlDecode and t:lowercase or t:normalisePath where appropriate to catch encoded payloads.
• For REST endpoints (wp/v2/posts), inspect JSON bodies for the content.rendered or content.raw fields.
• Monitor logs for false positives initially and refine rules.

WP‑Firewall-specific advice:

• Turn on "Virtual Patch" ruleset — this automatically deploys curated patterns for known shortcodes and XSS signatures.
• Add a custom rule using the regex above and enable action "Block + Alert."
• Enable request body inspection for admin endpoints and the WP REST API.
• Use the "Block by role" feature: if you have few Contributors, restrict POST endpoints to authenticated editors and above for public IP ranges.

These virtual patches are fast and reversible: ideal for protecting live sites until the plugin is updated or replaced.

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Developer remediation — secure code snippets and patterns

If you maintain the Ravelry Designs Widget plugin (or are a developer helping the maintainer), the permanent fix is to properly sanitize and escape all user-controlled input and use WordPress APIs. Here are best practices and example code.

1. Sanitize shortcode attributes at input time (server side). Use shortcode_atts() and sanitizers such as sanitize_text_field(), wp_kses() or whitelist-based validation.
2. Escape output according to context:
   • HTML attribute: use esc_attr()
   • HTML body: use esc_html() or wp_kses_post() if some HTML is allowed
   • URL: use esc_url()
   • JavaScript: JSON encode with wp_json_encode() and use esc_js() where appropriate
3. Example secure shortcode handler:

function sb_ravelry_designs_shortcode( $atts = [] ) {
    $defaults = array(
        'layout' => 'default',
        // other attributes...
    );

    // Merge with defaults and sanitize
    $atts = shortcode_atts( $defaults, $atts, 'sb_ravelry_designs' );

    // Whitelist/check allowed layouts — best option
    $allowed_layouts = array( 'default', 'compact', 'gallery' );
    $layout = in_array( $atts['layout'], $allowed_layouts, true ) ? $atts['layout'] : 'default';

    // If user-supplied free-form input is allowed, sanitize and escape:
    $layout_safe = sanitize_text_field( $layout ); // removes tags, control chars

    // Output context: inside an attribute
    $html = '<div class="ravelry-layout ' . esc_attr( $layout_safe ) . '">';
    // ... build safe output ...
    $html .= '</div>';

    return $html;
}
add_shortcode( 'sb_ravelry_designs', 'sb_ravelry_designs_shortcode' );

If layouts are complex templates rather than fixed names, use a mapping from a safe token (attribute) to a template file — never include raw user input into template filenames or HTML without strict validation.

3. Avoid unsafely echoing raw attributes:
   • NEVER directly echo $atts['layout'] into HTML.
   • Always sanitize and escape.
4. Unit and integration tests:
   • Add unit tests asserting that inputs containing <script> and other vectors are output safely encoded.
   • Test in a headless browser to ensure no script execution.
5. Extra defense: Content Security Policy (CSP)
   • Recommend site-wide CSP headers to block inline scripts and reduce XSS impact. CSP is an additional mitigation, not a substitute for input/output sanitization.

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Longer‑term hardening and operational recommendations

1. Minimize issuance of contributor accounts; implement review workflows. Contributors should be rare and tracked.
2. Implement content moderation: require editors to review and sanitize content from low‑privilege roles.
3. Regularly scan plugins and themes with automated scanners and keep them up to date.
4. Use staging for plugin/plugin updates and vulnerability testing.
5. Apply principle of least privilege on plugins: only enable plugins absolutely needed, and remove abandoned or unused plugins.
6. Adopt auto‑patching and virtual patches where possible: virtual patching buys time between disclosure and official plugin updates.
7. Enforce stricter input handling in custom shortcodes and theme template code.
8. Network hardening: implement WAF at the edge, rate limiting, and user‑behavior analytics to detect abnormal content submissions.

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Secure your site today with WP‑Firewall (Free plan details)

Title: Start with Essential Protection — Free WP‑Firewall Plan

If you want immediate protection while you investigate and remediate, WP‑Firewall offers a Free Basic plan that gives essential, always‑on defenses tailored for WordPress:

• Essential protection with a managed firewall and Web Application Firewall (WAF)
• Unlimited bandwidth through the protection layer
• Malware scanner to detect injected scripts and suspicious content
• Mitigations for OWASP Top 10 risks (including XSS patterns)
• Rapid virtual patching capability so known issues can be blocked before an official plugin update is available

Upgrade options are available if you need automated removal, IP allow/deny controls, auto virtual patching, monthly security reports, or managed security services.

Sign up for the free plan and enable protection in minutes: https://my.wp-firewall.com/buy/wp-firewall-free-plan/

(If you operate multiple sites or require vulnerability virtual patching, consider the Standard or Pro tiers to unlock automated removal, whitelist/blacklist controls, auto vulnerability patching, and managed remediation services.)

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Example incident response checklist (quick reference)

1. Disable the vulnerable plugin (or apply WAF rule).
2. Identify all posts containing [sb_ravelry_designs...].
3. Inspect and sanitize or remove suspicious posts.
4. Audit Contributor accounts and revoke or reset where necessary.
5. Rotate credentials for accounts that may have viewed an infected page.
6. Run malware scan and compare with backups.
7. Restore from clean backups if server files were modified.
8. Apply developer fixes and deploy an updated plugin version or remove plugin entirely.
9. Monitor logs and WAF alerts for repeat attempts.

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Why WP‑Firewall helps (practical benefits)

• Managed WAF rules are rapidly deliverable to your site as virtual patches — no need to wait on a plugin update.
• Custom rules targeted at admin endpoints and REST API reduce risk from authenticated, low‑privilege users.
• Continuous scanning helps identify whether the malicious content was stored and where.
• Incident logs and notification channels make it easier for you to act fast and reduce exposure windows.

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Conclusion

Stored XSS via shortcode attributes is a common pattern and a reminder that any user-supplied input — even attributes inside shortcodes — must be treated as untrusted. The chain from Contributor input → stored in the database → unsafe output → execution in a browser illustrates why output context‑aware escaping is mandatory.

If you run a WordPress site, act now:

• Audit posts for the vulnerable shortcode,
• Disable or update the plugin where possible,
• Apply virtual patching / WAF rules to block malicious payloads at the edge,
• Review contributor accounts and content moderation workflows,
• If you are a developer, push a fix that sanitizes and escapes attributes properly.

WP‑Firewall can help you block exploitation attempts quickly and provide ongoing protection while you apply permanent fixes. If you want assistance with rule creation, incident response, or managed remediation, our team is available to help.

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References & further reading

• CVE details
• WordPress Shortcodes
• Escaping for HTML
• OWASP XSS guidance

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If you'd like, our security team can produce a custom rule set for your site, review your posts for suspicious shortcodes, or run a deeper forensic check. Contact support via your WP‑Firewall dashboard for priority assistance.