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The vulnerability exists within the `helpers.markdown_extract()` function, which is responsible for processing user-supplied Markdown text and converting it to HTML for display. This function did not adequately sanitize malicious input before wrapping the content in an HTML literal element. An attacker can exploit this by creating or editing a dataset, resource, organization, or group page and injecting a crafted script payload within the resource description field. When this description is rendered on a public page, the malicious script is executed in the browser of any user viewing the page. This allows the attacker to perform actions on behalf of the victim user, potentially hijacking their session or defacing the site, because the unsafe output from the helper function is directly embedded into the page HTML without proper neutralization of active content.
Platform: CKAN
Version: < 2.10.9, < 2.11.4
Vulnerability : Stored XSS
Severity: Moderate
date: 2025-10-29
Prediction: Patch 2025-11-05
What Undercode Say:
Searching for the vulnerable helper function in a codebase grep -r "markdown_extract" /path/to/ckan/installation/ Example of a potentially malicious markdown payload for testing echo '![x](x" onerror="alert(1))' > test_payload.md
Example snippet showing vulnerable usage (conceptual) from ckan.lib.helpers import markdown_extract user_input is taken directly from a resource description without sufficient sanitization rendered_html = markdown_extract(user_input) rendered_html is then output unsafely, leading to XSS
How Exploit:
Attacker injects a malicious script payload into a resource description field using Markdown or HTML constructs. When an authenticated victim user views the page containing this malicious resource, the script executes automatically in their browser context.
Protection from this CVE
Upgrade CKAN to version 2.10.9 or 2.11.4. For immediate mitigation, implement strict output encoding for all data rendered from the `markdown_extract()` helper before it is inserted into the DOM.
Impact:
Execution of arbitrary JavaScript in the victim’s browser, leading to session hijacking, account takeover, or unauthorized actions performed on the user’s behalf.
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Sources:
Reported By: github.com
Extra Source Hub:
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