CVE-2026-54703

MEDIUMPre-NVD 5.85.8
EchelonGraph scoreMEDIUM confidence

“—” 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.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 3 sources updated this weekElevated
5.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.8Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
5.8
EG Score
5.8MEDIUMmedium confidence
EG Risk
42
EG 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, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available

0.8.30

Patch available: shd101wyy/vscode-markdown-preview-enhanced 0.8.30

https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30
GitHub commit Patch Available

commit 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/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e
GitHub pull request Patch Available

0.8.30

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/2323
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Arbitrary 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-2c42

Weakness 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.

  1. 2026-10-16 20:13 UTCEG score recompute
  2. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  4. 2026-10-15 15:30 UTCEG score recompute
  5. 2026-10-15 14:31 UTCEG score recompute
  6. 2026-10-15 14:24 UTCEG score recompute
  7. 2026-10-14 20:43 UTCEG score recompute
  8. 2026-10-14 19:28 UTCEG score recomputeFirst assessed: 5.8 MEDIUM
  9. 2026-10-14 19:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-54703?
CVE-2026-54703 is a medium-severity vulnerability; its CVE record was published on October 14, 2026. 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…
When was the CVE record for CVE-2026-54703 published?
The CVE record for CVE-2026-54703 was published on October 14, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 16, 2026; the record at its source may have been updated since.
Is CVE-2026-54703 actively exploited?
CVE-2026-54703 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (11th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-54703?
CVE-2026-54703 has a CVSS base score of 5.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-54703?
A fix for CVE-2026-54703 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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