CVE-2026-77088justhtml 0.9.0 through 1.21.0 Cross-Site Scripting via code-span
Updated under an hour ago ()
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It affects EmilStenstrom justhtml. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Free account, 1 product
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.
- CVSS
- 6.1 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Aug 29, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
EmilStenstrom justhtml emilstenstrom:justhtml (from the name) | from 0.9.0 through 1.21.0 | CNA record |
References
- https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-jf6w-2mvx-633jvendor-advisory
- https://www.vulncheck.com/advisories/justhtml-through-cross-site-scripting-via-code-spanthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.