CVE-2026-86543 (GCVE-0-2026-86543)
Vulnerability from cvelistv5 – Published: 2026-09-07 23:03 – Updated: 2026-09-07 23:03
VLAI
EPSS
VEX
Title
knowns before 0.30.0 Unauthenticated Management API Exposure
Summary
knowns versions before 0.30.0 serve the management API without authentication on all network interfaces by default, with no password required on fresh installations. Attackers can access the unauthenticated /api/tunnel/start endpoint to provision a public tunnel and republish the API at a publicly accessible address.
Severity
9.8 (Critical)
CWE
- CWE-306 - Missing Authentication for Critical Function
Assigner
References
7 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/blob/v0.29.1… | technical-description |
| https://github.com/knowns-dev/knowns/commit/878a0… | 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
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/knowns",
"product": "knowns",
"vendor": "knowns-dev",
"versions": [
{
"lessThan": "0.30.0",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "0.30.0",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "Tong Hoang Gia"
},
{
"lang": "en",
"type": "reporter",
"value": "Nguyen Huy Hoang"
}
],
"datePublic": "2026-08-16T00:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "knowns versions before 0.30.0 serve the management API without authentication on all network interfaces by default, with no password required on fresh installations. Attackers can access the unauthenticated /api/tunnel/start endpoint to provision a public tunnel and republish the API at a publicly accessible address."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 9.3,
"baseSeverity": "CRITICAL",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH"
},
"format": "CVSS"
},
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-306",
"description": "Missing Authentication for Critical Function",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-07T23:03:20.773Z",
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck"
},
"references": [
{
"name": "GitHub Security Advisory (GHSA-fc85-99vc-9c75)",
"tags": [
"vendor-advisory"
],
"url": "https://github.com/knowns-dev/knowns/security/advisories/GHSA-fc85-99vc-9c75"
},
{
"name": "AuthManager.Middleware is a no-op when no password is configured (v0.29.1)",
"tags": [
"technical-description"
],
"url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/auth.go#L80-L86"
},
{
"name": "Browser listener binds 0.0.0.0 (v0.29.1)",
"tags": [
"technical-description"
],
"url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/cli/browser.go#L193-L200"
},
{
"name": "POST /api/tunnel/start has no authorization check of its own (v0.29.1)",
"tags": [
"technical-description"
],
"url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/routes/tunnel.go#L26-L38"
},
{
"name": "knowns fix commit 878a02cb7cc1",
"tags": [
"patch"
],
"url": "https://github.com/knowns-dev/knowns/commit/878a02cb7cc14f0a592fdfda7a520af3cac500fb"
},
{
"name": "knowns v0.30.0 Release Notes",
"tags": [
"release-notes"
],
"url": "https://github.com/knowns-dev/knowns/releases/tag/v0.30.0"
},
{
"name": "VulnCheck Advisory: knowns before 0.30.0 Unauthenticated Management API Exposure",
"tags": [
"third-party-advisory"
],
"url": "https://www.vulncheck.com/advisories/knowns-before-0.30.0-unauthenticated-management-api-exposure"
}
],
"title": "knowns before 0.30.0 Unauthenticated Management API Exposure",
"x_generator": {
"engine": "vulncheck-endgame"
}
}
},
"cveMetadata": {
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"cveId": "CVE-2026-86543",
"datePublished": "2026-09-07T23:03:20.773Z",
"dateReserved": "2026-09-07T22:18:53.235Z",
"dateUpdated": "2026-09-07T23:03:20.773Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-86543",
"date": "2026-09-10",
"epss": "0.00443",
"percentile": "0.37392"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-86543\",\"sourceIdentifier\":\"disclosure@vulncheck.com\",\"published\":\"2026-09-07T23:16:54.160\",\"lastModified\":\"2026-09-08T19:56:50.950\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"knowns versions before 0.30.0 serve the management API without authentication on all network interfaces by default, with no password required on fresh installations. Attackers can access the unauthenticated /api/tunnel/start endpoint to provision a public tunnel and republish the API at a publicly accessible address.\"}],\"affected\":[{\"source\":\"disclosure@vulncheck.com\",\"affectedData\":[{\"vendor\":\"knowns-dev\",\"product\":\"knowns\",\"defaultStatus\":\"unaffected\",\"packageURL\":\"pkg:npm/knowns\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"0.30.0\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"0.30.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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\",\"baseScore\":9.3,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"HIGH\",\"vulnIntegrityImpact\":\"HIGH\",\"vulnAvailabilityImpact\":\"HIGH\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-306\"}]}],\"references\":[{\"url\":\"https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/cli/browser.go#L193-L200\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/auth.go#L80-L86\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/routes/tunnel.go#L26-L38\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/knowns-dev/knowns/commit/878a02cb7cc14f0a592fdfda7a520af3cac500fb\",\"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-fc85-99vc-9c75\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://www.vulncheck.com/advisories/knowns-before-0.30.0-unauthenticated-management-api-exposure\",\"source\":\"disclosure@vulncheck.com\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
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.
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