{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-3849", "assignerOrgId": "50d2cd11-d01a-48ed-9441-5bfce9d63b27", "state": "PUBLISHED", "assignerShortName": "wolfSSL", "dateReserved": "2026-03-09T19:50:50.081Z", "datePublished": "2026-03-19T20:29:30.839Z", "dateUpdated": "2026-03-19T20:29:30.839Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "50d2cd11-d01a-48ed-9441-5bfce9d63b27", "shortName": "wolfSSL", "dateUpdated": "2026-03-19T20:29:30.839Z"}, "title": "Buffer Overflow in HPKE via Oversized ECH Config", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-787", "description": "CWE-787: Out-of-bounds Write", "type": "CWE"}]}], "affected": [{"vendor": "wolfSSL Inc.", "product": "wolfSSL", "versions": [{"status": "affected", "version": "v5.6.0-stable", "lessThanOrEqual": "v5.8.4-stable", "versionType": "git"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client program crash. This could be exploited by a malicious TLS server supporting ECH. Note that ECH is off by default, and is only enabled with enable-ech.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<div>Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client program crash. This could be exploited by a malicious TLS server supporting ECH. Note that ECH is off by default, and is only enabled with enable-ech.</div><div><br></div>"}]}], "references": [{"url": "https://github.com/wolfSSL/wolfssl/pull/9737"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "DIFFUSE", "vulnerabilityResponseEffort": "MODERATE", "providerUrgency": "AMBER", "version": "4.0", "baseSeverity": "MEDIUM", "baseScore": 6.9, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/V:D/RE:M/U:Amber"}}], "credits": [{"lang": "en", "value": "Haruto Kimura (Stella)", "type": "finder"}], "source": {"discovery": "EXTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.0"}}}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Stack Buffer Overflow in wc_HpkeLabeledExtract via Oversized ECH Config. A vulnerability existed in wolfSSL 5.8.4 ECH (Encrypted Client Hello) support, where a maliciously crafted ECH config could cause a stack buffer overflow on the client side, leading to potential remote execution and client program crash. This could be exploited by a malicious TLS server supporting ECH. Note that ECH is off by default, and is only enabled with enable-ech."}], "id": "CVE-2026-3849", "lastModified": "2026-03-19T21:17:13.407", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.9, "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": "AMBER", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "DIFFUSE", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/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:D/RE:M/U:Amber", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "MODERATE"}, "source": "facts@wolfssl.com", "type": "Secondary"}]}, "published": "2026-03-19T21:17:13.407", "references": [{"source": "facts@wolfssl.com", "url": "https://github.com/wolfSSL/wolfssl/pull/9737"}], "sourceIdentifier": "facts@wolfssl.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-787"}], "source": "facts@wolfssl.com", "type": "Secondary"}]}

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