CVE-2025-12999: Eclipse Open VSX 0.6.0 through 1.1.2

Affected technology

Eclipse Open VSX · 0.6.0 through 1.1.2
Eclipse Foundation

Component: Not specified by the source

Attack conditions (Vendor/CNA, CVSS 4.0): Network (remote) · No privileges required · No user interaction required

What an attacker can do

An unauthenticated attacker can poison Open VSX's per-extension metadata cache with attacker-controlled download, signature, and public-key URLs by supplying a crafted X-Forwarded-Host header, causing downstream VS Code-compatible editors to fetch and install a malicious VSIX. Vendor/CNA’s CVSS 4.0 assessment (base score 9.1/10) rates confidentiality impact as none; integrity impact as high; availability impact as low.