Path Traversal in Eclipse Theia (CVE-2026-12609)
Summary
Path traversal in Eclipse Theia (CVE-2026-12609). Confidential information can be exposed externally.
Original description
The description as published by the source.
In Eclipse Theia versions 1.66.0 and up until including 1.73.1, the @theia/plugin-ext backend exposes the /hostedPlugin/:pluginId/:path(*) HTTP endpoint, which resolves the requested file path with path.resolve(localPath, filePath) without verifying that the resolved path stays within the plugin's directory. An unauthenticated network attacker can send percent-encoded ../ sequences (%2e%2e%2f) that decode into the path parameter and escape the plugin directory, allowing arbitrary files readable by the Theia backend process to be retrieved. Plugin IDs are derived deterministically from a plugin's publisher and name, so built-in plugins serve as reliable anchors that require no prior knowledge of the target system.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-12609 has been found in Eclipse Theia.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Eclipse Theia CVE-2026-12609" on the vendor's site.
CVE-2026-12609 (Eclipse Theia) — CWE-22 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in Eclipse Theia.
Check the vendor advisory for the affected versions of Eclipse Theia.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Eclipse Theia を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- report gitlab.eclipse.org
- web gitlab.eclipse.org
- web github.com