Vulnerability-Lookup

CVE-2026-86540 (GCVE-0-2026-86540)

Vulnerability from cvelistv5 – Published: 2026-09-07 23:03 – Updated: 2026-09-08 13:48

Title

knowns before 0.30.0 Arbitrary Code Execution via LSP Binary

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 with a crafted configuration is opened, the unvalidated binary path is executed twice under the user's account without any verification.

Severity

8.5 (High)


                        
                          CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

7.8 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-08 13:48 UTC

CWE

CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Assigner

VulnCheck mitre root

References

6 references

URL	Tags
https://github.com/knowns-dev/knowns/security/adv…	vendor-advisory
https://github.com/knowns-dev/knowns/blob/v0.29.1…	technical-description
https://github.com/knowns-dev/knowns/blob/v0.29.1…	technical-description
https://github.com/knowns-dev/knowns/commit/d3989…	patch
https://github.com/knowns-dev/knowns/releases/tag…	release-notes
https://www.vulncheck.com/advisories/knowns-befor…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
knowns-dev	knowns	Affected: 0 , < 0.30.0 (semver) Unaffected: 0.30.0 (semver)	guessed

Date Public

2026-08-16 00:00

Credits

Tong Hoang Gia Nguyen Huy Hoang

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-86540

Vulnerability from fkie_nvd - Published: 2026-09-07 23:16 - Updated: 2026-09-08 19:56

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Summary

References

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

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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          "id": "CVE-2026-86540",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-08T13:48:43.528505Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-07T23:16:53.723",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/lsp/detect.go#L128-L157"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/models/config.go#L205-L216"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/knowns-dev/knowns/commit/d3989829fb5095666d23d005b2f78a082832a396"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/knowns-dev/knowns/releases/tag/v0.30.0"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/knowns-dev/knowns/security/advisories/GHSA-mc52-mwq4-vfx3"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/knowns-before-0.30.0-arbitrary-code-execution-via-lsp-binary"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-78"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}

GHSA-6PH4-R249-58P2

Vulnerability from github – Published: 2026-09-08 00:30 – Updated: 2026-09-08 00:30

Details

Severity

7.8 (High)


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

8.5 (High)


                  
                    CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-86540"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-07T23:16:53Z",
    "severity": "HIGH"
  },
  "details": "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\u0027s account without any verification.",
  "id": "GHSA-6ph4-r249-58p2",
  "modified": "2026-09-08T00:30:22Z",
  "published": "2026-09-08T00:30:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/knowns-dev/knowns/security/advisories/GHSA-mc52-mwq4-vfx3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86540"
    },
    {
      "type": "WEB",
      "url": "https://github.com/knowns-dev/knowns/commit/d3989829fb5095666d23d005b2f78a082832a396"
    },
    {
      "type": "WEB",
      "url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/lsp/detect.go#L128-L157"
    },
    {
      "type": "WEB",
      "url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/models/config.go#L205-L216"
    },
    {
      "type": "WEB",
      "url": "https://github.com/knowns-dev/knowns/releases/tag/v0.30.0"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/knowns-before-0.30.0-arbitrary-code-execution-via-lsp-binary"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-86540 (GCVE-0-2026-86540)

FKIE_CVE-2026-86540

GHSA-6PH4-R249-58P2

Tags

Sightings

Nomenclature