CVE-2026-100868

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreHIGH confidence

Score 6.3 from GitHub Security Advisory published 2026-09-27. A secondary CVSS source baseline 6.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
6.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.3Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Penpot before 2.18.0 binds the MCP server plugin WebSocket bridge to all network interfaces without authentication in single-user mode. Unauthenticated attackers on adjacent networks can connect to the WebSocket port to impersonate the Penpot browser plugin, intercept task payloads, and return forged results to the MCP client.

CVSS v3
6.3
EG Score
6.3MEDIUMhigh confidence
EG Risk
44
EG Risk 44/100CISA SSVC

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
Severity63% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
15th
KEV
Not listed

CISA SSVCTrack 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). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 27, 2026

Last Modified

September 30, 2026

Advisory Details (6)

Auto-updated Sep 27, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
generic

Penpot before 2.18.0 Unauthenticated WebSocket Access via MCP Bridge | Advisories | VulnCheck

https://www.vulncheck.com/advisories/penpot-before-2.18.0-unauthenticated-websocket-access-via-mcp-bridge
github Patch Available🟡 PoC Available

Sibling of GHSA-22qr-rp27-j9wm: MCP plugin WebSocket bridge binds to all interfaces regardless of PENPOT_MCP_SERVER_HOST, no dev-flag required · Advisory · penpot/penpot · GitHub

https://github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r
github Patch Available🟡 PoC Available

MCP REPL server binds to 0.0.0.0 with unauthenticated /execute endpoint — RCE · Advisory · penpot/penpot · GitHub

https://github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm
github_commit Patch Available

commit b5274a44766d (penpot/penpot)

Patch available: penpot/penpot 2.18.0 (contains commit b5274a44766d)

https://github.com/penpot/penpot/commit/b5274a44766d095247037be18c1d1918ac67ddeb
generic

penpot/mcp/packages/server/src/PluginBridge.ts at 1d2c37e52c733f74017d90b0fd1ae2d074a5c33d · penpot/penpot · GitHub

https://github.com/penpot/penpot/blob/1d2c37e52c733f74017d90b0fd1ae2d074a5c33d/mcp/packages/server/src/PluginBridge.ts#L52
generic

GitHub - penpot/penpot: Penpot: The open-source design platform for Product teams that need scalable collaboration. · GitHub

https://github.com/penpot/penpot

Vendor Advisories for CVE-2026-100868(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 25× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

  1. 2026-10-04 23:21 UTCEPSS rescore
  2. 2026-10-04 18:45 UTCGHSA enrichment
  3. 2026-10-03 18:30 UTCEG score recompute
  4. 2026-10-03 18:30 UTCGHSA enrichment
  5. 2026-10-03 14:25 UTCEPSS rescore
  6. 2026-10-02 18:16 UTCGHSA enrichment
  7. 2026-10-02 18:16 UTCGHSA enrichment
  8. 2026-10-02 18:16 UTCEG score recompute
  9. 2026-10-02 18:16 UTCGHSA enrichment
  10. 2026-10-01 19:49 UTCEPSS rescore
  11. 2026-10-01 18:07 UTCGHSA enrichment
  12. 2026-09-30 17:47 UTCGHSA enrichment
  13. 2026-09-30 16:54 UTCEG score recompute
  14. 2026-09-30 16:54 UTCGHSA enrichment
  15. 2026-09-30 15:02 UTCEPSS rescore
  16. 2026-09-29 16:46 UTCEG score recompute
  17. 2026-09-29 16:46 UTCGHSA enrichment
  18. 2026-09-29 15:20 UTCEPSS rescore
  19. 2026-09-28 16:32 UTCEG score recompute
  20. 2026-09-28 16:32 UTCGHSA enrichment
  21. 2026-09-28 15:52 UTCEG score recompute
  22. 2026-09-28 15:52 UTCGHSA enrichment
  23. 2026-09-28 13:50 UTCEPSS rescore
  24. 2026-09-28 13:26 UTCEG score recompute
  25. 2026-09-28 13:26 UTCGHSA enrichment
Show 3 more
  1. 2026-09-27 13:18 UTCEG score recompute
  2. 2026-09-27 13:16 UTCEG score recompute
  3. 2026-09-27 13:15 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-100868?
CVE-2026-100868 is a medium vulnerability published on September 27, 2026. Penpot before 2.18.0 binds the MCP server plugin WebSocket bridge to all network interfaces without authentication in single-user mode. Unauthenticated attackers on adjacent networks can connect to the WebSocket port to impersonate the Penpot browser plugin, intercept task payloads, and return…
When was CVE-2026-100868 disclosed?
CVE-2026-100868 was first published on September 27, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-100868 actively exploited?
CVE-2026-100868 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100868?
CVE-2026-100868 has a CVSS base score of 6.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100868?
A fix for CVE-2026-100868 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-100868 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-100868

Explore →

Is Your Infrastructure Affected by CVE-2026-100868?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs