Vulnerability · Published Sep 7, 2026 · Assigned by VulnCheck
CVE-2026-86540knowns before 0.30.0 Arbitrary Code Execution via LSP Binary
High 7.8
In plain English
A high-severity OS command injection in knowns from knowns-dev. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
knowns versions before 0.30.0 fail to validate the settings.lsp.languages binary field in project configuration files, allowing attackers to execute arbitrary binaries by crafting a malicious .knowns/config.json file. When a repository with a crafted configuration is opened, the unvalidated binary path is executed twice under the user's account without any verification.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | knowns | 0.30.0 | GHSA-mc52-mwq4-vfx3 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| knowns-dev | knowns | 0 – before 0.30.0 |
Weakness: CWE-78 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- GitHub Security Advisory (GHSA-mc52-mwq4-vfx3) vendor-advisory
- Detector.resolve executes the unvalidated binary override (v0.29.1) technical-description
- ProjectSettings.Validate does not inspect the LSP binary field (v0.29.1) technical-description
- knowns fix commit d3989829fb50 patch
- knowns v0.30.0 Release Notes release-notes
- VulnCheck Advisory: knowns before 0.30.0 Arbitrary Code Execution via LSP Binary third-party-advisory