justhtml 0.9.0 through 1.21.0 Cross-Site Scripting via code-span (CVE-2026-77088) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-77088

justhtml 0.9.0 through 1.21.0 Cross-Site Scripting via code-span

Answer in brief

CVE-2026-77088 records a Unknown severity vulnerability in justhtml 0.9.0 through 1.21.0 Cross-Site Scripting via code-span. The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 23, 2026Updated Aug 23, 2026Source checked Aug 23, 2026First seen by HOL Aug 23, 2026Material review Aug 23, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: Not mapped
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

Affected software not mapped in the current feed; confirm the named product and version against your inventory.

Recommended response

Confirm exposure. Identify whether the named product or interface exists in your inventory, then review the linked upstream references for affected versions and vendor guidance.

Evidence timeline and material changes

Published upstream
Aug 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 23, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.