CVE-2026-10054

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 94% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In affected versions of Eclipse Theia (1.8.1 and later), the browser backend exposes privileged terminal RPC over WebSocket (/services/shell-terminal, /services/terminals/:id) without service-level authentication.

WebSocket origin validation in @theia/core is fail-open: connections are accepted when the Origin header is missing or when no THEIA_HOSTS allowlist is configured (the default). The Socket.IO integration additionally replaces the real Origin header with a client-supplied fix-origin header that an attacker can control or omit.

As a result, a foreign-origin web page visited by a user with a running Theia instance can open the /services WebSocket namespace, invoke terminal creation, attach to the resulting terminal data channel, execute arbitrary OS commands, and read their output. This affects both local developer setups (drive-by attack) and hosted or tunneled deployments without strong external authentication.

A fix is in development that enforces same-origin validation by default, removes trust in the fix-origin header, gates HTTP and WebSocket access on a SameSite=Strict; HttpOnly connection-token cookie, and sanitizes shell terminal creation options.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
5.5%
KEV
Not listed

Published

July 3, 2026

Last Modified

July 7, 2026

Advisory Details (2)

Auto-updated Jul 3, 2026
Patch available. Sources: github.
generic

[Eclipse Theia] Cross-Origin WebSocket Access To Shell-Terminal Enables Command Execution And Output Exfiltration (#376) · Issues · Eclipse Projects Security / vulnerability-reports · GitLab

https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/376
github Patch Available

Cross-Origin WebSocket Access To Shell-Terminal Enables Command Execution And Output Exfiltration · Advisory · eclipse-theia/theia · GitHub

https://github.com/eclipse-theia/theia/security/advisories/GHSA-78g8-vm3p-97c6

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 23× in last 7d / 27× 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. 2026-07-11 15:11 UTCEG score recompute
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-11 03:01 UTCEG score recompute
  4. 2026-07-10 14:50 UTCEG score recompute
  5. 2026-07-10 02:41 UTCEG score recompute
  6. 2026-07-09 19:10 UTCEPSS rescore
  7. 2026-07-09 14:30 UTCEG score recompute
  8. 2026-07-09 02:17 UTCEG score recompute
  9. 2026-07-08 15:15 UTCEPSS rescore
  10. 2026-07-08 15:15 UTCEPSS rescore
  11. 2026-07-08 14:08 UTCEG score recompute
  12. 2026-07-08 01:59 UTCEG score recompute
  13. 2026-07-07 13:50 UTCEG score recompute
  14. 2026-07-07 13:46 UTCEPSS rescore
  15. 2026-07-07 01:40 UTCEG score recompute
  16. 2026-07-06 16:27 UTCEPSS rescore
  17. 2026-07-06 13:31 UTCEG score recompute
  18. 2026-07-06 02:23 UTCEPSS rescore
  19. 2026-07-06 01:19 UTCEG score recompute
  20. 2026-07-05 13:10 UTCEG score recompute
  21. 2026-07-05 02:30 UTCEPSS rescore
  22. 2026-07-05 02:30 UTCEPSS rescore
  23. 2026-07-05 01:01 UTCEG score recompute
  24. 2026-07-04 12:48 UTCEG score recompute
  25. 2026-07-04 00:39 UTCEG score recompute
Show 2 more
  1. 2026-07-03 12:28 UTCEG score recompute
  2. 2026-07-03 12:26 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-10054?
CVE-2026-10054 is a high vulnerability published on July 3, 2026. In affected versions of Eclipse Theia (1.8.1 and later), the browser backend exposes privileged terminal RPC over WebSocket (/services/shell-terminal, /services/terminals/:id) without service-level authentication. WebSocket origin validation in @theia/core is fail-open: connections are accepted…
When was CVE-2026-10054 disclosed?
CVE-2026-10054 was first published in the National Vulnerability Database on July 3, 2026, with the most recent update on July 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-10054 actively exploited?
CVE-2026-10054 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-10054?
CVE-2026-10054 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-10054?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-10054, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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