What is CVE-2026-86540?

CVE-2026-86540 is a high-severity vulnerability in Knowns-Dev Knowns, classified under OS Command Injection. CVSS score: 7.8/10. Published 2026-09-07.

How severe is CVE-2026-86540?

High severity. CVSS v3 base score is 7.8 out of 10.

RCE in Knowns-Dev Knowns

CVE-2026-86540

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.

Vulnerability class: Command Injection (OS Command Injection)

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Knowns-dev Knowns

Weakness classification (CWE)

CWE-78 — OS Command Injection

References

disclosure@vulncheck.com (technical-description)
disclosure@vulncheck.com (technical-description)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (release-notes)
disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-86540?: CVE-2026-86540 is a high-severity vulnerability in Knowns-Dev Knowns, classified under OS Command Injection. CVSS score: 7.8/10. Published 2026-09-07.
How severe is CVE-2026-86540?: High severity. CVSS v3 base score is 7.8 out of 10.