mediumVulnerability

GHSA-qvc2-mg72-jjhx

## Summary Sanitized DOM trees can be unsafe to serialize when a custom policy allows raw-text elements such as `<style>` or `<script>`. The issue affects DOM trees that are constructed or modified programmatically and then passed through `sanitize_dom()` with a policy that keeps these elements. Text nodes inside `<style>` and `<script>` are serialized literally, so attacker-controlled text containing the matching closing tag sequence can break out of the raw-text context and inject HTML into the serialized output. The default sanitization policy is not affected because it drops the contents of `style` and `script`. ## Details The root cause is in HTML serialization of raw-text elements. In serialize.py, text children of `script` and `style` are emitted verbatim: ```python _LITERAL_TEXT_SERIALIZATION_ELEMENTS = frozenset({"script", "style"}) def _serialize_text_for_parent(text: str | None, parent_name: str | None) -> str: if not text: return "" if parent_name in _LITERAL_TEXT_SERIALIZATION_ELEMENTS: return text return _escape_text(text)

Properties

ghsa_id
GHSA-qvc2-mg72-jjhx
severity
medium
summary
JustHTML Affected by Mutation XSS via Literal Text Serialization in Raw Text Elements (style/script)
cve_id
GHSA-qvc2-mg72-jjhx
is_ghsa_only
true
ghsa_published
2026-03-18T20:19:47Z
source_url
https://github.com/advisories/GHSA-qvc2-mg72-jjhx
ghsa_updated
2026-03-18T20:19:48Z

Related Entities (3)

AFFECTS (1)

[Software]pip/justhtml

HAS_WEAKNESS (1)

[Weakness]Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

REPORTED_BY (1)

[Source]GitHub Advisory Database

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