CVE-2026-86541 (GCVE-0-2026-86541)
Vulnerability from cvelistv5 – Published: 2026-09-07 23:03 – Updated: 2026-09-07 23:03
VLAI
EPSS
VEX
Title
knowns before 0.30.0 Path Traversal via code.replace MCP action
Summary
knowns versions before 0.30.0 contain a path traversal vulnerability in the handleCodeReplace() function that allows attackers to overwrite arbitrary files outside the project root. Attackers can supply absolute paths or relative paths containing directory traversal sequences to write malicious content to sensitive files like shell startup scripts or SSH configuration files.
Severity
CWE
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
5 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/commit/a2c98… | 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
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"credits": [
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"type": "reporter",
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}
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"providerMetadata": {
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"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
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"url": "https://github.com/knowns-dev/knowns/security/advisories/GHSA-f539-xgc6-xw7q"
},
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"tags": [
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"url": "https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/mcp/handlers/code.go#L588-L646"
},
{
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},
{
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"tags": [
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],
"url": "https://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-code-replace-mcp-action"
}
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"title": "knowns before 0.30.0 Path Traversal via code.replace MCP action",
"x_generator": {
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}
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"cveMetadata": {
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"cveId": "CVE-2026-86541",
"datePublished": "2026-09-07T23:03:19.358Z",
"dateReserved": "2026-09-07T22:18:48.043Z",
"dateUpdated": "2026-09-07T23:03:19.358Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-86541",
"date": "2026-09-09",
"epss": "0.00533",
"percentile": "0.43274"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-86541\",\"sourceIdentifier\":\"disclosure@vulncheck.com\",\"published\":\"2026-09-07T23:16:53.863\",\"lastModified\":\"2026-09-08T19:56:50.950\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"knowns versions before 0.30.0 contain a path traversal vulnerability in the handleCodeReplace() function that allows attackers to overwrite arbitrary files outside the project root. Attackers can supply absolute paths or relative paths containing directory traversal sequences to write malicious content to sensitive files like shell startup scripts or SSH configuration files.\"}],\"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:P/VC:L/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\":7.2,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"PASSIVE\",\"vulnConfidentialityImpact\":\"LOW\",\"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:R/S:U/C:L/I:H/A:H\",\"baseScore\":8.3,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.8,\"impactScore\":5.5}]},\"weaknesses\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-22\"}]}],\"references\":[{\"url\":\"https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/mcp/handlers/code.go#L588-L646\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/knowns-dev/knowns/commit/a2c98fc5c313463576c9348beeec6a74ddd7333b\",\"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-f539-xgc6-xw7q\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-code-replace-mcp-action\",\"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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