Uncontrolled recursion DoS in JustHTML() via deeply nested HTML

Summaryjusthtml through 1.9.1 allows denial of service via deeply nested HTML. During parsing, JustHTML.init always reaches TreeBuilder.finish, which unconditionally calls populateselectedcontent. That function recursively traverses the DOM via findelements / findelement without a depth bound,...

PYSEC-2026-3854 Uncontrolled recursion DoS in JustHTML() via deeply nested HTML

Summary justhtml through 1.9.1 allows denial of service via deeply nested HTML. During parsing, JustHTML.init always reaches TreeBuilder.finish, which unconditionally calls populateselectedcontent. That function recursively traverses the DOM via findelements / findelement without a depth bound,...

Duplicate Advisory: Uncontrolled recursion DoS in JustHTML() via deeply nested HTML

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-v7cf-c9rm-wm3j. This link is maintained to preserve external references. Original Description justhtml through 1.9.1 fixed in 1.10.0 is vulnerable to uncontrolled recursion leading to denial of service. During...

CVE-2026-9769

justhtml through 1.9.1 fixed in 1.10.0 is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML construction, TreeBuilder.finish unconditionally calls populateselectedcontent, which recursively traverses the DOM tree via findelements/findelement without a depth bound...

CVE-2026-8630

justhtml before 1.12.0 versions and . When a DOM tree is processed by sanitizedom 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...

CVE-2026-77088

justhtml versions 0.9.0 through 1.21.0 contain a cross-site scripting vulnerability in tomarkdown 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...

CVE-2026-8445

justhtml versions are preserved, so untrusted input that is safe in tohtml — including entity-decoded text e.g. script or text from RCDATA/RAWTEXT-parsed elements like , , , and — can be emitted as raw HTML in the Markdown output, enabling a sanitizer bypass and potential cross-site scripting whe...

CVE-2026-74793

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...

CVE-2026-7808

justhtml before 1.16.0 contains multiple HTML sanitization bypass issues that can allow active/dangerous content e.g., script or style to survive sanitization, potentially leading to cross-site scripting. The issues primarily affect advanced usage rather than the default JustHTML..., sanitize=Tru...

CVE-2026-6827

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 , MathML and mutation-XSS parser-differential payloads could...

CVE-2026-5389

justhtml versions before 1.13.0 contain a cross-site scripting vulnerability in the tomarkdown function when serializing attacker-controlled pre content. Attackers can place backticks inside sanitized pre elements to break out of fixed-length code fences, allowing raw HTML to execute when the...

CVE-2026-5751

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., dropforeignnamespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

CVE-2026-5388

justhtml before 1.15.0 contains multiple security issues in URL sanitization helpers cleanurlvalue/cleanurlinjsstring, HTML serialization, Markdown passthrough htmlpassthrough=True, and several custom sanitization-policy edge cases. Depending on configuration, an attacker can bypass sanitization ...

CVE-2026-4671

justhtml before 1.18.0 contains multiple low-severity denial-of-service issues in CSS selector handling and linkification. Applications that evaluate attacker-controlled selector strings via query, matches, or selector-based transforms, run selector matching over very large untrusted documents,...

CVE-2026-9769 justhtml before 1.10.0 Denial of Service via deeply nested HTML

justhtml through 1.9.1 fixed in 1.10.0 is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML construction, TreeBuilder.finish unconditionally calls populateselectedcontent, which recursively traverses the DOM tree via findelements/findelement without a depth bound...

CVE-2026-9769 justhtml before 1.10.0 Denial of Service via deeply nested HTML

justhtml through 1.9.1 fixed in 1.10.0 is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML construction, TreeBuilder.finish unconditionally calls populateselectedcontent, which recursively traverses the DOM tree via findelements/findelement without a depth bound...

CVE-2026-9769 justhtml before 1.10.0 Denial of Service via deeply nested HTML

justhtml through 1.9.1 fixed in 1.10.0 is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML construction, TreeBuilder.finish unconditionally calls populateselectedcontent, which recursively traverses the DOM tree via findelements/findelement without a depth bound...

EUVD-2026-64661

justhtml through 1.9.1 fixed in 1.10.0 is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML construction, TreeBuilder.finish unconditionally calls populateselectedcontent, which recursively traverses the DOM tree via findelements/findelement without a depth bound...

CVE-2026-9769

justhtml (Python HTML parser) through version 1.9.1 is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML() construction, TreeBuilder.finish() unconditionally calls _populate_selectedcontent(), which recursively traverses the DOM tree via _find_elements()/_find_ele...

CVE-2026-8630 justhtml before 1.12.0 Mutation XSS via Raw Text Elements

justhtml before 1.12.0 versions and . When a DOM tree is processed by sanitizedom 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...