How severe is CVE-2026-46580?

CVE-2026-46580 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-46580 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-46580?

CVE-2026-46580 affects Eclipse Theia. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-46580?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-46580 have an EU (EUVD) identifier?

Yes. CVE-2026-46580 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37899.

When was CVE-2026-46580 published?

CVE-2026-46580 was published on 2026-06-18 and last updated on 2026-06-22.

CVE-2026-46580

CVE-2026-46580 is a high-severity vulnerability in Eclipse Theia with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-829.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 8.4
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-37899
Weakness: CWE-829
Affected product: Eclipse Theia
Published: 2026-06-18
Last modified: 2026-06-22

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.

Frequently asked questions

What is CVE-2026-46580?: 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.
How severe is CVE-2026-46580?: CVE-2026-46580 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-46580 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-46580?: CVE-2026-46580 affects Eclipse Theia. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-46580?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-46580 have an EU (EUVD) identifier?: Yes. CVE-2026-46580 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37899.
When was CVE-2026-46580 published?: CVE-2026-46580 was published on 2026-06-18 and last updated on 2026-06-22.

References

https://gitlab.eclipse.org/security/cve-assignment/-/work_items/114

Affected products (1)

cpe:2.3:a:eclipse:theia:*:*:*:*:*:*:*:*

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