HTML injection via literal raw-text serialization
Published Aug 23, 2026 · Updated Aug 23, 2026
Mutation XSS in JustHTML before 1.12.0 allows attackers to inject arbitrary HTML through sanitized DOM serialization. In serialize.py, _serialize_text_for_parent() emits text children of script and style elements verbatim instead of escaping matching closing-tag sequences. Exploitation requires a programmatically constructed or modified DOM and a custom policy that preserves those elements; the default policy drops their contents.
Summary
What happened
Mutation XSS in JustHTML before 1.12.0 allows attackers to inject arbitrary HTML through sanitized DOM serialization. In serialize.py, _serialize_text_for_parent() emits text children of script and style elements verbatim instead of escaping matching closing-tag sequences. Exploitation requires a programmatically constructed or modified DOM and a custom policy that preserves those elements; the default policy drops their contents.
The record
- CVE
- CVE-2026-8630
- Published
- Aug 23, 2026
- Updated
- Aug 23, 2026
- Vendor
- Emil Stenström
- Product
- JustHTML
- Classifications
- CWE-79, T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 23, 2026CVE publishedPublication date reported by the CVE source.
- Aug 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <1.12.0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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