---
id: CVE-2026-86540
title: >-
  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
summary: >-
  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 w…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
vendor: knowns-dev
product: knowns
affected:
  - knowns < 0.30.0
published: '2026-09-07'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T19:56:50.950'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86540'
references:
  - url: >-
      https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/lsp/detect.go#L128-L157
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/models/config.go#L205-L216
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/knowns-dev/knowns/commit/d3989829fb5095666d23d005b2f78a082832a396
    label: disclosure@vulncheck.com
  - url: 'https://github.com/knowns-dev/knowns/releases/tag/v0.30.0'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/knowns-dev/knowns/security/advisories/GHSA-mc52-mwq4-vfx3
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/knowns-before-0.30.0-arbitrary-code-execution-via-lsp-binary
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00212
epssPercentile: 0.10284
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-08T13:48:43.528505Z'
ingestedAt: '2026-09-08T15:33:26.980Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.