CVE-2026-54701
MEDIUM 6.9Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, Markdown Preview Enhanced reads repository-controlled .crossnote/head.html content and passes it through resolvePathsInHeader before inserting it into the head of the preview webview document without removing executable content. Script-capable markup executes while the document loads, before the React application and DOMPurify initialize, and can access acquireVsCodeApi to send messages from the webview to the extension host. Opening a Markdown preview in a malicious repository is sufficient to trigger the injected content, and no additional click within the notification or preview is required. This issue is fixed in version 0.8.30.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 22nd percentile
Impact if exploited
6.9CVSS 4.0 · MEDIUM
- ConfidentialityLow
- IntegrityHigh
- AvailabilityLow
What an attacker needs
- ⚠Access: Requires local access to the host
- ✓Privileges: No account or privileges required
- ⚠User interaction: Succeeds with passive user activity
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
Search for new PoCs
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Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Data snapshot:
Weakness (CWE)
- CWE-79: : Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N
References and research data (JSON)
All CVSS metrics
- MEDIUM 6.9 v4.0 · CNA Primary
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N - MEDIUM 6.9 v4.0 · NVD Secondary
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
References
Exploit-tagged references (not proof of a PoC)
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3 CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
CVE record · CISA-ADP · Updated 2026-10-20T02:01:15.836Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-101584 EUVD · EUVD-2026-101584
Technical & other
- https://github.com/shd101wyy/crossnote/pull/444 CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347 - https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323 CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347 - https://github.com/shd101wyy/crossnote/commit/8c55a2ba3365712a1caa4abeece0383bc2994d48 CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347 - https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347 - https://github.com/shd101wyy/crossnote/releases/tag/0.9.31 CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347 - https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30 CVE record · GitHub_M · Updated 2026-10-14T19:11:51.712Z
NVD · CVE-2026-54701 · Updated 2026-10-20T03:17:15.347