CVE-2026-12856
The extension incorrectly trusts all Markdown content in JavaDoc hovers, allowing a malicious Java file to include hidden commands.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.55%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 0.55% probability · 44th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-88
- Affected
- redhat/openshift dev spaces
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:36820
- https://access.redhat.com/security/cve/CVE-2026-12856Mitigation, Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2491278Issue Tracking, Vendor Advisory
- https://github.com/redhat-developer/vscode-java/security/advisories/GHSA-7qv8-6qrw-3crvBroken Link
- https://access.redhat.com/errata/RHSA-2026:36820
- https://access.redhat.com/security/cve/CVE-2026-12856Mitigation, Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2491278Issue Tracking, Vendor Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12856.jsonVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.