CVE-2026-126393

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-126393", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-11-10T21:30:16.910Z", "datePublished": "2026-11-13T09:35:52.971Z", "dateUpdated": "2026-11-13T09:35:52.971Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-11-13T09:35:52.971Z"}, "datePublic": "2026-10-29T00:00:00.000Z", "title": "SiYuan before 3.8.10 SSRF via Skill-Install Download Redirect and DNS Rebinding", "descriptions": [{"lang": "en", "value": "SiYuan before 3.8.10 contains a server-side request forgery vulnerability in the skill-install download path because fetchBytes performs only a parse-time hostname check instead of using ssrfSafeClient. Attackers can supply a skill URL via the MCP skill install action that redirects or DNS-rebinds to loopback addresses, reaching internal services and metadata endpoints."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Server-Side Request Forgery (SSRF)", "cweId": "CWE-918", "type": "CWE"}]}], "affected": [{"vendor": "siyuan-note", "product": "siyuan", "defaultStatus": "unaffected", "versions": [{"version": "0", "status": "affected", "versionType": "semver", "lessThan": "3.8.10"}, {"version": "3.8.10", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.8.10"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE", "baseScore": 6.1, "baseSeverity": "MEDIUM"}}], "references": [{"url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6pg3-pqxw-jm82", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-6pg3-pqxw-jm82)"}, {"name": "VulnCheck Advisory: SiYuan before 3.8.10 SSRF via Skill-Install Download Redirect and DNS Rebinding", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/siyuan-before-3.8.10-ssrf-via-skill-install-download-redirect-and-dns-rebinding"}], "credits": [{"lang": "en", "value": "Figo5", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "siyuan", "vendor": "siyuan-note", "versions": [{"lessThan": "3.8.10", "status": "affected", "version": "0", "versionType": "semver"}, {"status": "unaffected", "version": "3.8.10", "versionType": "semver"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "SiYuan before 3.8.10 contains a server-side request forgery vulnerability in the skill-install download path because fetchBytes performs only a parse-time hostname check instead of using ssrfSafeClient. Attackers can supply a skill URL via the MCP skill install action that redirects or DNS-rebinds to loopback addresses, reaching internal services and metadata endpoints."}], "id": "CVE-2026-126393", "lastModified": "2026-11-13T10:17:43.333", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.7, "source": "disclosure@vulncheck.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 5.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}]}, "published": "2026-11-13T10:17:43.207", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6pg3-pqxw-jm82"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/siyuan-before-3.8.10-ssrf-via-skill-install-download-redirect-and-dns-rebinding"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-918"}], "source": "disclosure@vulncheck.com", "type": "Primary"}]}

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