[Aikido] Fix 9 security issues in erb, rails-html-sanitizer, loofah

[aikido-autofix]

Upgrade ERB, rails-html-sanitizer, and Loofah to fix RCE via marshal deserialization and XSS via unrestricted SVG href attributes.

✅ 9 CVEs resolved by this upgrade

This PR will resolve the following CVEs:

Issue	Severity	Description
AIKIDO-2026-467095	MEDIUM	[erb] A marshal deserialization vulnerability allows attackers to bypass execution guards in ERB by overriding the equal? method on a crafted @_init object, enabling arbitrary code execution through template evaluation. The fix uses BasicObject#equal? to prevent the bypass.
GHSA-cj75-f6xr-r4g7	LOW	[rails-html-sanitizer] A cross-site scripting (XSS) vulnerability exists when the sanitizer is configured to allow SVG reference elements like <use>. This permits attackers to inject malicious scripts through SVG local references.
AIKIDO-2026-663658	LOW	[rails-html-sanitizer] A Cross-site Scripting (XSS) vulnerability exists due to incomplete attribute restrictions on SVG elements, allowing href attributes to reference external documents and potentially execute scripts or load external content for tracking purposes.
AIKIDO-2026-622262	LOW	[loofah] HTML5 sanitizer fails to restrict the href attribute on SVG elements, allowing Cross-site Scripting (XSS) attacks through external document references in elements like <use> and <feImage>. This enables arbitrary script execution or external content loading when sanitizing user-supplied SVG.
GHSA-9wjq-cp2p-hrgf	LOW	[loofah] Loofah's HTML5 sanitizer failed to restrict the href attribute on SVG elements, allowing external document references that could execute scripts or enable tracking through SVG and elements.
AIKIDO-2026-349881	LOW	[loofah] A Cross-site Scripting (XSS) vulnerability exists due to improper validation of URIs with numeric character references lacking trailing semicolons, allowing malicious scripts like javascript&#58alert(1) to bypass filtering and execute in browsers.
AIKIDO-2026-498891	LOW	[loofah] A vulnerability in the allowed_uri? helper fails to reject javascript: URIs when the scheme is split by HTML5 named character references like &Tab; or &NewLine;, allowing attackers to bypass URI validation and execute arbitrary JavaScript. This affects callers of the public helper method and higher-level features like Action Text markdown link validation that render approved URIs into HTML attributes.
GHSA-5qhf-9phg-95m2	LOW	[loofah] A bypass vulnerability in URI validation allows javascript: and vbscript: schemes to evade filtering when split by numeric character references without trailing semicolons, enabling XSS attacks through browser URI decoding.
GHSA-8whx-365g-h9vv	LOW	[loofah] A bypass vulnerability in URI scheme validation allows javascript: URIs to be executed when prefixed with HTML5 named character references ( or ), circumventing existing security filters and enabling XSS attacks.

🔗 Related Tasks

• https://aikido.atlassian.net/browse/AIK-17450

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[aikido-autofix]

Closed by Aikido: a new AutoFix has been created → #345