{"id":"CVE-2026-10054","details":"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.\n\n\n\n\nWebSocket 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.\n\n\n\n\nAs 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.\n\n\n\n\nA 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.","aliases":["GHSA-78g8-vm3p-97c6"],"modified":"2026-08-12T03:51:25.599255892Z","published":"2026-07-03T10:11:32.446Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10054.json","cna_assigner":"eclipse","cwe_ids":["CWE-1385","CWE-306"]},"references":[{"type":"WEB","url":"https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/376"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10054.json"},{"type":"ADVISORY","url":"https://github.com/eclipse-theia/theia/security/advisories/GHSA-78g8-vm3p-97c6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-10054"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/eclipse-theia/theia","events":[{"introduced":"65edb153bd37f322a45c6c928d757e4090ba3265"},{"fixed":"72573426f320fefc89a96ba55ce05c752d182123"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"1.8.1"},{"fixed":"1.73.0"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-10054.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}