{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-5187", "assignerOrgId": "50d2cd11-d01a-48ed-9441-5bfce9d63b27", "state": "PUBLISHED", "assignerShortName": "wolfSSL", "dateReserved": "2026-03-30T19:57:33.843Z", "datePublished": "2026-04-09T19:45:39.937Z", "dateUpdated": "2026-04-09T19:45:39.937Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "50d2cd11-d01a-48ed-9441-5bfce9d63b27", "shortName": "wolfSSL", "dateUpdated": "2026-04-09T19:45:39.937Z"}, "title": "Heap Out-of-Bounds Write in DecodeObjectId() in wolfSSL", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-122", "description": "CWE-122: Heap-based Buffer Overflow", "type": "CWE"}]}, {"descriptions": [{"lang": "en", "cweId": "CWE-787", "description": "CWE-787: Out-of-bounds Write", "type": "CWE"}]}], "affected": [{"vendor": "wolfSSL", "product": "wolfSSL", "modules": ["wolfcrypt/src/asn.c"], "programFiles": ["wolfcrypt/src/asn.c"], "versions": [{"status": "affected", "version": "0", "lessThanOrEqual": "5.9.0", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second, multiple callers pass sizeof(decOid) (64 bytes on 64-bit platforms) instead of the element count MAX_OID_SZ (32), causing the function to accept crafted OIDs with 33 or more arcs that write past the end of the allocated buffer.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second, multiple callers pass sizeof(decOid) (64 bytes on 64-bit platforms) instead of the element count MAX_OID_SZ (32), causing the function to accept crafted OIDs with 33 or more arcs that write past the end of the allocated buffer.<br></p>"}]}], "references": [{"url": "https://github.com/wolfSSL/wolfssl", "name": "wolfSSL GitHub Repository"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "LOW", "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": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "LOW", "baseScore": 2.3, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N"}}], "configurations": [{"lang": "en", "value": "Bug 1 (off-by-one) affects any code calling DecodeObjectId() with an output buffer of size 1. Bug 2 (sizeof mismatch) is reachable via network when wolfSSL is compiled with HAVE_OID_DECODING or WOLFSSL_ASN_PRINT, and WC_ASN_UNKNOWN_EXT_CB is enabled with a registered unknown extension callback.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Bug 1 (off-by-one) affects any code calling DecodeObjectId() with an output buffer of size 1. Bug 2 (sizeof mismatch) is reachable via network when wolfSSL is compiled with HAVE_OID_DECODING or WOLFSSL_ASN_PRINT, and WC_ASN_UNKNOWN_EXT_CB is enabled with a registered unknown extension callback.</p>"}]}], "workarounds": [{"lang": "en", "value": "Do not enable WC_ASN_UNKNOWN_EXT_CB or do not register an unknown extension callback if not required. This mitigates the network-reachable variant (Bug 2) but does not address Bug 1.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Do not enable WC_ASN_UNKNOWN_EXT_CB or do not register an unknown extension callback if not required. This mitigates the network-reachable variant (Bug 2) but does not address Bug 1.</p>"}]}], "solutions": [{"lang": "en", "value": "Fix Bug 1: Add a bounds check requiring at least 2 output slots before writing the first OID arc split (y == 0 case). Fix Bug 2: Change callers to pass the element count (MAX_OID_SZ) instead of sizeof(decOid) as the output buffer size parameter.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Fix Bug 1: Add a bounds check requiring at least 2 output slots before writing the first OID arc split (y == 0 case). Fix Bug 2: Change callers to pass the element count (MAX_OID_SZ) instead of sizeof(decOid) as the output buffer size parameter.</p>"}]}], "credits": [{"lang": "en", "value": "ytsun, Independent Security Researcher", "type": "finder"}], "source": {"discovery": "UNKNOWN"}, "x_generator": {"engine": "Vulnogram 1.0.1"}}}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second, multiple callers pass sizeof(decOid) (64 bytes on 64-bit platforms) instead of the element count MAX_OID_SZ (32), causing the function to accept crafted OIDs with 33 or more arcs that write past the end of the allocated buffer."}], "id": "CVE-2026-5187", "lastModified": "2026-04-09T20:16:28.233", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 2.3, "baseSeverity": "LOW", "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": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/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:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "facts@wolfssl.com", "type": "Secondary"}]}, "published": "2026-04-09T20:16:28.233", "references": [{"source": "facts@wolfssl.com", "url": "https://github.com/wolfSSL/wolfssl"}], "sourceIdentifier": "facts@wolfssl.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-122"}, {"lang": "en", "value": "CWE-787"}], "source": "facts@wolfssl.com", "type": "Secondary"}]}

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