Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, the _crossnote.updateMarkdown command in Markdown Preview Enhanced accepts an arbitrary URI and attacker-controlled content, then passes them to vscode.workspace.fs.writeFile without validating that the target is the Markdown file represented by the current preview. JavaScript already executing in the preview webview can invoke this command through the extension message bridge and write any file permitted by the VS Code user's operating-system privileges, including user configuration, startup, source, and build files. This file-write vulnerability requires a separate webview JavaScript execution path, such as the independently tracked head.html injection and blind command-dispatch weaknesses. This issue is fixed in version 0.8.30.
CVE-2026-54703
“—” beside the score: it is equal to the CVSS score beside it.
This medium-severity CVE scores 5.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (11th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 5.8
- EG Score
- 5.8MEDIUMmedium confidence
- EG Risk
- 42EG Risk 42/100
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computed (value × EchelonGraph’s weight)Severity58% × 45%The EG Score, 5.8 of 10.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.2%
- EPSS %ILE
- 11th
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 14, 2026
Last Modified
October 16, 2026
Advisory Details (4)
Auto-updated Oct 14, 20260.8.30
Patch available: shd101wyy/vscode-markdown-preview-enhanced 0.8.30
https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30commit 8bc848b6cbb4 (shd101wyy/vscode-markdown-preview-enhanced)
Patch available: shd101wyy/vscode-markdown-preview-enhanced 0.8.30 (contains commit 8bc848b6cbb4)
https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e0.8.30
Patch available: shd101wyy/vscode-markdown-preview-enhanced 0.8.30 (PR #2323 merged 2026-06-08)
https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323Arbitrary File Write via updateMarkdown Command Without Path Validation · Advisory · shd101wyy/vscode-markdown-preview-enhanced · GitHub
https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-82rc-7g3m-2c42Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-10-16 20:13 UTCEG score recompute
- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
- 2026-10-15 15:30 UTCEG score recompute
- 2026-10-15 14:31 UTCEG score recompute
- 2026-10-15 14:24 UTCEG score recompute
- 2026-10-14 20:43 UTCEG score recompute
- 2026-10-14 19:28 UTCEG score recomputeFirst assessed: 5.8 MEDIUM
- 2026-10-14 19:24 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-54703
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