CVE-2026-12856: A flaw was found in the vscode-java extension, which provides Java language support for Visual Studio Code

This month

HIGH 8.8WATCHLISTMITIGATE

CVE-2026-12856 is a high-severity flaw (CVSS 8.8) affecting openshift dev spaces. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.5% (top 54%)
CISA exploited list	No
Weakness	CWE-88
Published	2026-06-29
Last modified	2026-10-25

Publisher (CNA): Red Hat, Inc. · Vendor: redhat

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-29 14:16 UTCPublished CVE record published
2026-10-25 21:10 UTCUpdated Record last modified

redhat openshift dev spaces MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openshift-dev-spaces || rpm -q openshift-dev-spaces || openshift-dev-spaces --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-12856?

openshift dev spaces: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-12856 being exploited?

CVE-2026-12856 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-12856 affect?

CVE-2026-12856 affects openshift dev spaces. Severity is high (CVSS 8.8). 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.

How urgent is CVE-2026-12856?

Priority 47/100. High severity; On your watchlist

Software pages

Java vulnerabilities · Visual Studio vulnerabilities · Red Hat OpenShift vulnerabilities

References

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