CVE-2026-86540: Command Injection (CVSS 7.8)

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.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-78 OS Command Injection

References

Other References

https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/lsp/detect.go#L128-L157 https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/models/config.go#L205-L216 https://github.com/knowns-dev/knowns/commit/d3989829fb5095666d23d005b2f78a082832a396 https://github.com/knowns-dev/knowns/releases/tag/v0.30.0 https://github.com/knowns-dev/knowns/security/advisories/GHSA-mc52-mwq4-vfx3 https://www.vulncheck.com/advisories/knowns-before-0.30.0-arbitrary-code-execution-via-lsp-binary

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-86540? +

CVE-2026-86540 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0015, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-86540? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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