CVE-2026-77088
justhtml versions 0.9.0 through 1.21.0 contain a cross-site scripting vulnerability in to_markdown() where inline code spans fail to account
CVSS
6.1
Medium
EPSS
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KEV
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Exploit Today
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0-100
Published: Aug 23, 2026 · Last modified: Aug 23, 2026 · CWE-79
Not enough EPSS history yet.
justhtml versions 0.9.0 through 1.21.0 contain a cross-site scripting vulnerability in to_markdown() where inline code spans fail to account for blank lines as block boundaries. Attackers can inject blank lines into code or pre element text to break the inline span, causing sanitized HTML to be emitted unescaped and re-parsed as live Markdown by compliant renderers.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-781873.1 LOW—
———A vulnerability has been found in Piwigo 16.3.0. This impacts an unknown function of the component Public Authentication Page. Such manipulation of the argument lang leads to cross site scripting. The attack may be performed from remote. A high complexity level is associated with this attack. The exploitability is said to be difficult. The exploit has been disclosed to the public and may be used. Upgrading to version 16.4.0 will fix this issue. The name of the patch is 5277a7dee4b8f1a174f1d69e1e2a4e1c82a3fc9e. It is recommended to upgrade the affected component.2hCVE-2026-782138.7 HIG—
———Heptabase developed by Hepta Platforms, Inc. has a Stored Cross-Site Scripting vulnerability. Authenticated remote attackers can inject persistent malicious content into specific pages, causing arbitrary JavaScript code to execute when other users click the crafted content.3hCVE-2026-86306.1 MED—
———justhtml before 1.12.0 (versions <= 1.11.0) contains a mutation cross-site scripting (mXSS) vulnerability in the serialization of raw-text elements such as <style> and <script>. When a DOM tree is processed by sanitize_dom() using a custom policy that keeps these elements, text nodes inside them are serialized literally without escaping, allowing attacker-controlled text containing the matching closing tag sequence to break out of the raw-text context and inject arbitrary HTML into the serialized output. The default sanitization policy is not affected because it drops the contents of style and script.17hCVE-2026-84459.8 CRI—
———justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape HTML-significant characters (angle brackets) in text nodes when converting a parsed document to Markdown via to_markdown(). While a small set of Markdown metacharacters are escaped, characters such as < and > are preserved, so untrusted input that is safe in to_html() — including entity-decoded text (e.g. <script>) or text from RCDATA/RAWTEXT-parsed elements like <title>, <textarea>, <noscript>, and <plaintext> — can be emitted as raw HTML in the Markdown output, enabling a sanitizer bypass and potential cross-site scripting when that output is rendered.17hCVE-2026-747936.1 MED—
———justhtml before 3.11.0 contains a cross-site scripting vulnerability where the default sanitizer bypasses event handler removal in selectedcontent projections. Attackers can inject SVG or MathML elements with event handlers that are cloned and reinserted into output without sanitization, enabling stored or reflected XSS attacks.17hCVE-2026-68276.1 MED—
———justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling. When custom policies preserve foreign namespaces (SVG/MathML), dangerous content such as HTML integration points (SVG <foreignObject>, MathML <annotation-xml encoding="text/html">) and mutation-XSS parser-differential payloads could survive sanitization and become active HTML after reparse; SVG filter="url(...)" and preserved <style> could leave resource-loading CSS (@import, background-image:url()). Programmatic script/style/Comment nodes could serialize into active markup. Additional hardening fixes address sanitize-pipeline cache mutation and DOM parent/child cycles that could cause infinite loops. Most issues affect advanced or custom configurations rather than the default JustHTML(..., sanitize=True) safe path.17h