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CVE-2026-46580 Eclipse Foundation CVE debrief

CVE-2026-46580 is a HIGH-severity vulnerability in Eclipse Theia, a cloud-native, multi-protocol IDE framework. In versions prior to 1.71.0, Theia automatically loaded files matching the pattern `.prompts/*.prompttemplate` in a workspace, allowing an attacker to craft malicious repository containing prompt template files. When a workspace was opened in Theia, these files could replace the AI's system instructions with attacker-controlled content, enabling indirect prompt injection. This vulnerability, combined with other AI chat features available in untrusted workspaces, could lead to data exfiltration via Markdown image rendering or arbitrary command execution via task definitions. Users of affected Theia versions should update to 1.71.0 or later to mitigate this vulnerability.

Vendor
Eclipse Foundation
Product
Eclipse Theia
CVSS
HIGH 8.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-18
Original CVE updated
2026-06-22
Advisory published
2026-06-18
Advisory updated
2026-06-22

Who should care

Developers and users of Eclipse Theia, especially those working with AI-powered features in untrusted workspaces, should be aware of this vulnerability. Additionally, security teams and administrators responsible for managing and securing development environments should take note of this issue and ensure that Theia instances are updated to a secure version.

Technical summary

The vulnerability exists in Eclipse Theia versions prior to 1.71.0. Theia's automatic loading of `.prompts/*.prompttemplate` files in a workspace allows an attacker to inject malicious prompts. This can be exploited through a crafted repository, enabling indirect prompt injection when the workspace is opened. The CVSS score for this vulnerability is 8.4, indicating a HIGH severity level. The CVSS vector is 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

Defensive priority

HIGH

Recommended defensive actions

  • Update Eclipse Theia to version 1.71.0 or later
  • Verify that all workspaces and repositories are trusted before opening them in Theia
  • Implement strict access controls for workspaces and repositories
  • Monitor for suspicious activity in Theia workspaces
  • Use secure protocols for data exchange and storage
  • Regularly review and update Theia and its dependencies

Evidence notes

The information provided is based on data from the NVD and CVE.org. The CVE record and NVD detail pages provide official information about the vulnerability. The source item URL provides additional context from the NVD's vulnerability database.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46580 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46580

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-46580 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46580

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.