CVE-2026-59710

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{"bugzilla": {"description": "showdown: Showdown: Stored Cross-Site Scripting via unescaped table header ID attributes in markdown", "id": "2497554", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2497554"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "status": "draft"}, "cwe": "CWE-79", "details": ["showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.", "A flaw was found in Showdown. This vulnerability, a stored cross-site scripting (XSS) issue, allows an attacker to inject malicious code into web pages. By exploiting unescaped table header ID attributes in markdown, an attacker can embed arbitrary HTML and script-executing elements. When untrusted markdown is processed, this can lead to the execution of malicious scripts in a user's web browser, potentially compromising user data or session integrity."], "mitigation": {"lang": "en:us", "value": "To mitigate this vulnerability, avoid rendering untrusted markdown content within applications utilizing Showdown. If processing untrusted markdown is unavoidable, ensure that all input is thoroughly sanitized before rendering to prevent the injection of malicious HTML or script-executing elements."}, "name": "CVE-2026-59710", "package_state": [{"cpe": "cpe:/a:redhat:cryostat:4", "fix_state": "Fix deferred", "package_name": "cryostat-openshift-console-plugin-npm", "product_name": "Cryostat 4"}, {"cpe": "cpe:/a:redhat:cryostat:4", "fix_state": "Fix deferred", "package_name": "showdown", "product_name": "Cryostat 4"}, {"cpe": "cpe:/a:redhat:multicluster_engine", "fix_state": "Fix deferred", "package_name": "multicluster-engine/console-mce-rhel9", "product_name": "Multicluster Engine for Kubernetes"}, {"cpe": "cpe:/a:redhat:workload_availability_nhc:0", "fix_state": "Fix deferred", "package_name": "workload-availability/node-healthcheck-must-gather-rhel9", "product_name": "Node HealthCheck Operator"}, {"cpe": "cpe:/a:redhat:workload_availability_nhc:0", "fix_state": "Fix deferred", "package_name": 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["https://www.cve.org/CVERecord?id=CVE-2026-59710\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-59710\nhttps://github.com/showdownjs/showdown\nhttps://github.com/showdownjs/showdown/commit/e5cab1e9a5dcea2bb3cbf888863fa7e65ab37edf\nhttps://github.com/showdownjs/showdown/issues/1046\nhttps://www.vulncheck.com/advisories/showdown-stored-xss-via-unescaped-table-header-id-attribute-injection"], "statement": "Showdown, as integrated into Red Hat products, is susceptible to a stored cross-site scripting vulnerability. This flaw allows an attacker to inject arbitrary HTML and script-executing SVG elements by exploiting unescaped table header ID attributes within markdown. When untrusted markdown is rendered using the default GitHub flavor configuration, malicious scripts can execute in a user's web browser, potentially compromising data or session integrity. Affected versions: <= 2.1.0.", "threat_severity": "Moderate"}

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