Vulnerability · Published Jun 18, 2026 · Assigned by eclipse
CVE-2026-46580
High 8.4
In plain English
A high-severity security flaw in Eclipse Theia from Eclipse Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
In Eclipse Theia versions prior to 1.71.0, files matching the pattern .prompts/*.prompttemplate in a workspace were automatically loaded and could override or extend the AI agent's system prompts. An attacker could craft a malicious repository containing prompt template files that, when the workspace was opened in Theia, replaced the AI's system instructions with attacker-controlled content (indirect prompt injection). Combined with other AI chat features available in untrusted workspaces, this enabled attack chains leading to data exfiltration via Markdown image rendering or arbitrary command execution via task definitions.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @theia/ai-chat | 1.71.0 | GHSA-m973-pr9r-hp2w |
| npm | @theia/ai-chat-ui | 1.71.0 | GHSA-m973-pr9r-hp2w |
| npm | @theia/ai-claude-code | 1.71.0 | GHSA-m973-pr9r-hp2w |
| npm | @theia/ai-code-completion | 1.71.0 | GHSA-m973-pr9r-hp2w |
| npm | @theia/ai-core | 1.71.0 | GHSA-m973-pr9r-hp2w |
| npm | @theia/ai-editor | 1.71.0 | GHSA-m973-pr9r-hp2w |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Eclipse Foundation | Eclipse Theia | 0 – before 1.71.0 |
Weakness: CWE-829, CWE-1427 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N