CVE-2026-7383 (GCVE-0-2026-7383)
Vulnerability from cvelistv5 – Published: 2026-06-09 16:03 – Updated: 2026-06-10 07:47- CWE-787 - Out-of-bounds Write
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| OpenSSL | OpenSSL |
Affected:
4.0.0 , < 4.0.1
(semver)
Affected: 3.6.0 , < 3.6.3 (semver) Affected: 3.5.0 , < 3.5.7 (semver) Affected: 3.4.0 , < 3.4.6 (semver) Affected: 3.0.0 , < 3.0.21 (semver) Affected: 1.1.1 , < 1.1.1zh (custom) Affected: 1.0.2 , < 1.0.2zq (custom) |
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-7383",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-09T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-06-10T03:58:57.944Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "OpenSSL",
"vendor": "OpenSSL",
"versions": [
{
"lessThan": "4.0.1",
"status": "affected",
"version": "4.0.0",
"versionType": "semver"
},
{
"lessThan": "3.6.3",
"status": "affected",
"version": "3.6.0",
"versionType": "semver"
},
{
"lessThan": "3.5.7",
"status": "affected",
"version": "3.5.0",
"versionType": "semver"
},
{
"lessThan": "3.4.6",
"status": "affected",
"version": "3.4.0",
"versionType": "semver"
},
{
"lessThan": "3.0.21",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
},
{
"lessThan": "1.1.1zh",
"status": "affected",
"version": "1.1.1",
"versionType": "custom"
},
{
"lessThan": "1.0.2zq",
"status": "affected",
"version": "1.0.2",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "Zehua Qiao"
},
{
"lang": "en",
"type": "reporter",
"value": "Jinwen He"
},
{
"lang": "en",
"type": "remediation developer",
"value": "Viktor Dukhovni"
}
],
"datePublic": "2026-06-09T14:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Issue summary: A signed integer overflow when sizing the destination\u003cbr\u003ebuffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap\u003cbr\u003ebuffer overflow.\u003cbr\u003e\u003cbr\u003eImpact summary: A heap buffer overflow may lead to a crash or possibly\u003cbr\u003eattacker controlled code execution or other undefined behaviour.\u003cbr\u003e\u003cbr\u003eIn ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination\u003cbr\u003esize for Unicode output is computed in a signed int: by left shift\u003cbr\u003eof the input character count for BMPSTRING (UTF-16) and\u003cbr\u003eUNIVERSALSTRING (UTF-32), and by summing per-character byte counts\u003cbr\u003efor UTF8STRING. The calculation overflows when the input reaches\u003cbr\u003earound 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30\u003cbr\u003echaracters) the size wraps to zero, OPENSSL_malloc(1) is called, and\u003cbr\u003ethe subsequent character copy writes several gigabytes past the\u003cbr\u003eone-byte allocation.\u003cbr\u003e\u003cbr\u003eX.509 certificate processing routes through ASN1_STRING_set_by_NID(),\u003cbr\u003ewhose DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID\u003cbr\u003esize limits cap the input length; no network protocol or\u003cbr\u003ecertificate-handling path in OpenSSL exercises the overflow.\u003cbr\u003eTriggering the bug requires an application that calls\u003cbr\u003eASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers\u003cbr\u003ea custom string type via ASN1_STRING_TABLE_add(), with\u003cbr\u003eattacker-controlled input on the order of half a gigabyte or more.\u003cbr\u003eFor these reasons this issue was assigned Low severity.\u003cbr\u003e\u003cbr\u003eThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\u003cbr\u003ethis issue, as the affected code is outside the OpenSSL FIPS module\u003cbr\u003eboundary."
}
],
"value": "Issue summary: A signed integer overflow when sizing the destination\nbuffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap\nbuffer overflow.\n\nImpact summary: A heap buffer overflow may lead to a crash or possibly\nattacker controlled code execution or other undefined behaviour.\n\nIn ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination\nsize for Unicode output is computed in a signed int: by left shift\nof the input character count for BMPSTRING (UTF-16) and\nUNIVERSALSTRING (UTF-32), and by summing per-character byte counts\nfor UTF8STRING. The calculation overflows when the input reaches\naround 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30\ncharacters) the size wraps to zero, OPENSSL_malloc(1) is called, and\nthe subsequent character copy writes several gigabytes past the\none-byte allocation.\n\nX.509 certificate processing routes through ASN1_STRING_set_by_NID(),\nwhose DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID\nsize limits cap the input length; no network protocol or\ncertificate-handling path in OpenSSL exercises the overflow.\nTriggering the bug requires an application that calls\nASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers\na custom string type via ASN1_STRING_TABLE_add(), with\nattacker-controlled input on the order of half a gigabyte or more.\nFor these reasons this issue was assigned Low severity.\n\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\nthis issue, as the affected code is outside the OpenSSL FIPS module\nboundary."
}
],
"metrics": [
{
"format": "other",
"other": {
"content": {
"text": "Low"
},
"type": "https://openssl-library.org/policies/general/security-policy/"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-787",
"description": "CWE-787 Out-of-bounds Write",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-10T07:47:47.578Z",
"orgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
"shortName": "openssl"
},
"references": [
{
"name": "OpenSSL Advisory",
"tags": [
"vendor-advisory"
],
"url": "https://openssl-library.org/news/secadv/20260609.txt"
},
{
"name": "4.0.1 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/d32350ae8ef7426718f5aa9e383d4b51398ee255"
},
{
"name": "3.6.3 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/c332adaced43bcbb85f97410597e951c11ec3083"
},
{
"name": "3.5.7 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/80c15faaf78042bbb8654a0e234c50c381732f74"
},
{
"name": "3.4.6 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/4f8d2bddaa2c8e06f9c33390ee1717059a6e4be6"
},
{
"name": "3.0.21 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/bd17511070fb39a67bfa19682affb765e706a974"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion",
"x_generator": {
"engine": "Vulnogram 0.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
"assignerShortName": "openssl",
"cveId": "CVE-2026-7383",
"datePublished": "2026-06-09T16:03:15.508Z",
"dateReserved": "2026-04-29T08:21:07.253Z",
"dateUpdated": "2026-06-10T07:47:47.578Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-7383",
"date": "2026-11-13",
"epss": "0.00804",
"percentile": "0.57281"
},
"microsoft_vex": {
"current_release_date": "2026-11-12T17:32:39.000Z",
"cve": "CVE-2026-7383",
"id": "msrc_CVE-2026-7383",
"initial_release_date": "2026-06-13T01:03:46.000Z",
"product_status:fixed": "3",
"product_status:known_affected": "4",
"product_status:known_not_affected": "9",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-7383.json",
"version": "9"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "OpenSSL",
"vendor": "OpenSSL",
"versions": [
{
"lessThan": "4.0.1",
"status": "affected",
"version": "4.0.0",
"versionType": "semver"
},
{
"lessThan": "3.6.3",
"status": "affected",
"version": "3.6.0",
"versionType": "semver"
},
{
"lessThan": "3.5.7",
"status": "affected",
"version": "3.5.0",
"versionType": "semver"
},
{
"lessThan": "3.4.6",
"status": "affected",
"version": "3.4.0",
"versionType": "semver"
},
{
"lessThan": "3.0.21",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
},
{
"lessThan": "1.1.1zh",
"status": "affected",
"version": "1.1.1",
"versionType": "custom"
},
{
"lessThan": "1.0.2zq",
"status": "affected",
"version": "1.0.2",
"versionType": "custom"
}
]
}
],
"source": "openssl-security@openssl.org"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "F534B804-67B6-49DA-8A86-0FF21E512908",
"versionEndExcluding": "1.0.2zq",
"versionStartIncluding": "1.0.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "43EFE1E3-4049-4EE6-A2AE-BDBA38E6870F",
"versionEndExcluding": "1.1.1zh",
"versionStartIncluding": "1.1.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "EDB88756-EDFE-4886-A267-3F19342A6042",
"versionEndExcluding": "3.0.21",
"versionStartIncluding": "3.0.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "BF7E21E7-AEC0-4882-B1F1-2D056B506F22",
"versionEndExcluding": "3.4.6",
"versionStartIncluding": "3.4.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "6B6B9930-C549-4D88-9784-AF32CCDDB87A",
"versionEndExcluding": "3.5.7",
"versionStartIncluding": "3.5.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"matchCriteriaId": "D41B3C45-EC73-4DC8-989D-B2E2792E102F",
"versionEndExcluding": "3.6.3",
"versionStartIncluding": "3.6.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:*",
"matchCriteriaId": "6E881B9A-1A0A-4BC0-8160-20C00561167D",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Issue summary: A signed integer overflow when sizing the destination\nbuffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap\nbuffer overflow.\n\nImpact summary: A heap buffer overflow may lead to a crash or possibly\nattacker controlled code execution or other undefined behaviour.\n\nIn ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination\nsize for Unicode output is computed in a signed int: by left shift\nof the input character count for BMPSTRING (UTF-16) and\nUNIVERSALSTRING (UTF-32), and by summing per-character byte counts\nfor UTF8STRING. The calculation overflows when the input reaches\naround 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30\ncharacters) the size wraps to zero, OPENSSL_malloc(1) is called, and\nthe subsequent character copy writes several gigabytes past the\none-byte allocation.\n\nX.509 certificate processing routes through ASN1_STRING_set_by_NID(),\nwhose DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID\nsize limits cap the input length; no network protocol or\ncertificate-handling path in OpenSSL exercises the overflow.\nTriggering the bug requires an application that calls\nASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers\na custom string type via ASN1_STRING_TABLE_add(), with\nattacker-controlled input on the order of half a gigabyte or more.\nFor these reasons this issue was assigned Low severity.\n\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\nthis issue, as the affected code is outside the OpenSSL FIPS module\nboundary."
},
{
"lang": "es",
"value": "Resumen del problema: Un desbordamiento de entero con signo al dimensionar el b\u00fafer de destino para la salida Unicode en ASN1_mbstring_ncopy() puede conducir a un desbordamiento de b\u00fafer de pila.\n\nResumen del impacto: Un desbordamiento de b\u00fafer de pila puede conducir a un fallo o posiblemente a la ejecuci\u00f3n de c\u00f3digo controlado por el atacante u otro comportamiento indefinido.\n\nEn ASN1_mbstring_copy() y ASN1_mbstring_ncopy() el tama\u00f1o de destino para la salida Unicode se calcula en un entero con signo: mediante un desplazamiento a la izquierda del recuento de caracteres de entrada para BMPSTRING (UTF-16) y UNIVERSALSTRING (UTF-32), y sumando los recuentos de bytes por car\u00e1cter para UTF8STRING. El c\u00e1lculo desborda cuando la entrada alcanza alrededor de 2^30 caracteres. En el peor de los casos (UNIVERSALSTRING con 2^30 caracteres) el tama\u00f1o se ajusta a cero, se llama a OPENSSL_malloc(1), y la copia de caracteres subsiguiente escribe varios gigabytes m\u00e1s all\u00e1 de la asignaci\u00f3n de un byte.\n\nEl procesamiento de certificados X.509 se encamina a trav\u00e9s de ASN1_STRING_set_by_NID(), cuya m\u00e1scara DIRSTRING_TYPE excluye UNIVERSALSTRING y cuyos l\u00edmites de tama\u00f1o por NID restringen la longitud de entrada; ning\u00fan protocolo de red o ruta de manejo de certificados en OpenSSL ejerce el desbordamiento. Activar el error requiere una aplicaci\u00f3n que llama a ASN1_mbstring_copy() o ASN1_mbstring_ncopy() directamente, o registra un tipo de cadena personalizado a trav\u00e9s de ASN1_STRING_TABLE_add(), con entrada controlada por el atacante del orden de medio gigabyte o m\u00e1s. Por estas razones, a este problema se le asign\u00f3 una severidad Baja.\n\nLos m\u00f3dulos FIPS en 4.0, 3.6, 3.5, 3.4 y 3.0 no se ven afectados por este problema, ya que el c\u00f3digo afectado est\u00e1 fuera del l\u00edmite del m\u00f3dulo FIPS de OpenSSL."
}
],
"id": "CVE-2026-7383",
"lastModified": "2026-07-23T08:10:00.137",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.2,
"impactScore": 5.9,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-7383",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-09T00:00:00+00:00",
"version": "2.0.3"
}
}
]
},
"published": "2026-06-09T17:17:50.337",
"references": [
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/4f8d2bddaa2c8e06f9c33390ee1717059a6e4be6"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/80c15faaf78042bbb8654a0e234c50c381732f74"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/bd17511070fb39a67bfa19682affb765e706a974"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/c332adaced43bcbb85f97410597e951c11ec3083"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Patch"
],
"url": "https://github.com/openssl/openssl/commit/d32350ae8ef7426718f5aa9e383d4b51398ee255"
},
{
"source": "openssl-security@openssl.org",
"tags": [
"Vendor Advisory"
],
"url": "https://openssl-library.org/news/secadv/20260609.txt"
}
],
"sourceIdentifier": "openssl-security@openssl.org",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-787"
}
],
"source": "openssl-security@openssl.org",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-11-07T04:36:39+00:00",
"cve": "CVE-2026-7383",
"id": "CVE-2026-7383",
"initial_release_date": "2026-06-09T00:00:00+00:00",
"product_status:fixed": "207",
"product_status:known_affected": "47",
"product_status:known_not_affected": "124",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "openssl: OpenSSL: Heap buffer overflow due to signed integer overflow in Unicode output sizing",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-7383.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "moderate",
"current_release_date": "2026-11-11T02:50:02Z",
"cve": "CVE-2026-7383",
"id": "CVE-2026-7383",
"initial_release_date": "2026-06-13T02:29:31Z",
"product_status:known_affected": "568",
"product_status:known_not_affected": "111",
"product_status:recommended": "354",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-7383",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-7383.json",
"version": "22"
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-7383",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-09T16:48:52.179678Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-06-09T16:48:48.573Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "OpenSSL",
"vendor": "OpenSSL",
"versions": [
{
"lessThan": "4.0.1",
"status": "affected",
"version": "4.0.0",
"versionType": "semver"
},
{
"lessThan": "3.6.3",
"status": "affected",
"version": "3.6.0",
"versionType": "semver"
},
{
"lessThan": "3.5.7",
"status": "affected",
"version": "3.5.0",
"versionType": "semver"
},
{
"lessThan": "3.4.6",
"status": "affected",
"version": "3.4.0",
"versionType": "semver"
},
{
"lessThan": "3.0.21",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
},
{
"lessThan": "1.1.1zh",
"status": "affected",
"version": "1.1.1",
"versionType": "custom"
},
{
"lessThan": "1.0.2zq",
"status": "affected",
"version": "1.0.2",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "Zehua Qiao"
},
{
"lang": "en",
"type": "reporter",
"value": "Jinwen He"
},
{
"lang": "en",
"type": "remediation developer",
"value": "Viktor Dukhovni"
}
],
"datePublic": "2026-06-09T14:00:00.000Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Issue summary: A signed integer overflow when sizing the destination\u003cbr\u003ebuffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap\u003cbr\u003ebuffer overflow.\u003cbr\u003e\u003cbr\u003eImpact summary: A heap buffer overflow may lead to a crash or possibly\u003cbr\u003eattacker controlled code execution or other undefined behaviour.\u003cbr\u003e\u003cbr\u003eIn ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination\u003cbr\u003esize for Unicode output is computed in a signed int: by left shift\u003cbr\u003eof the input character count for BMPSTRING (UTF-16) and\u003cbr\u003eUNIVERSALSTRING (UTF-32), and by summing per-character byte counts\u003cbr\u003efor UTF8STRING. The calculation overflows when the input reaches\u003cbr\u003earound 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30\u003cbr\u003echaracters) the size wraps to zero, OPENSSL_malloc(1) is called, and\u003cbr\u003ethe subsequent character copy writes several gigabytes past the\u003cbr\u003eone-byte allocation.\u003cbr\u003e\u003cbr\u003eX.509 certificate processing routes through ASN1_STRING_set_by_NID(),\u003cbr\u003ewhose DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID\u003cbr\u003esize limits cap the input length; no network protocol or\u003cbr\u003ecertificate-handling path in OpenSSL exercises the overflow.\u003cbr\u003eTriggering the bug requires an application that calls\u003cbr\u003eASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers\u003cbr\u003ea custom string type via ASN1_STRING_TABLE_add(), with\u003cbr\u003eattacker-controlled input on the order of half a gigabyte or more.\u003cbr\u003eFor these reasons this issue was assigned Low severity.\u003cbr\u003e\u003cbr\u003eThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\u003cbr\u003ethis issue, as the affected code is outside the OpenSSL FIPS module\u003cbr\u003eboundary."
}
],
"value": "Issue summary: A signed integer overflow when sizing the destination\nbuffer for Unicode output in ASN1_mbstring_ncopy() can lead to a heap\nbuffer overflow.\n\nImpact summary: A heap buffer overflow may lead to a crash or possibly\nattacker controlled code execution or other undefined behaviour.\n\nIn ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination\nsize for Unicode output is computed in a signed int: by left shift\nof the input character count for BMPSTRING (UTF-16) and\nUNIVERSALSTRING (UTF-32), and by summing per-character byte counts\nfor UTF8STRING. The calculation overflows when the input reaches\naround 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30\ncharacters) the size wraps to zero, OPENSSL_malloc(1) is called, and\nthe subsequent character copy writes several gigabytes past the\none-byte allocation.\n\nX.509 certificate processing routes through ASN1_STRING_set_by_NID(),\nwhose DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID\nsize limits cap the input length; no network protocol or\ncertificate-handling path in OpenSSL exercises the overflow.\nTriggering the bug requires an application that calls\nASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers\na custom string type via ASN1_STRING_TABLE_add(), with\nattacker-controlled input on the order of half a gigabyte or more.\nFor these reasons this issue was assigned Low severity.\n\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by\nthis issue, as the affected code is outside the OpenSSL FIPS module\nboundary."
}
],
"metrics": [
{
"format": "other",
"other": {
"content": {
"text": "Low"
},
"type": "https://openssl-library.org/policies/general/security-policy/"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-787",
"description": "CWE-787 Out-of-bounds Write",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-10T07:47:47.578Z",
"orgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
"shortName": "openssl"
},
"references": [
{
"name": "OpenSSL Advisory",
"tags": [
"vendor-advisory"
],
"url": "https://openssl-library.org/news/secadv/20260609.txt"
},
{
"name": "4.0.1 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/d32350ae8ef7426718f5aa9e383d4b51398ee255"
},
{
"name": "3.6.3 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/c332adaced43bcbb85f97410597e951c11ec3083"
},
{
"name": "3.5.7 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/80c15faaf78042bbb8654a0e234c50c381732f74"
},
{
"name": "3.4.6 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/4f8d2bddaa2c8e06f9c33390ee1717059a6e4be6"
},
{
"name": "3.0.21 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/bd17511070fb39a67bfa19682affb765e706a974"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion",
"x_generator": {
"engine": "Vulnogram 0.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
"assignerShortName": "openssl",
"cveId": "CVE-2026-7383",
"datePublished": "2026-06-09T16:03:15.508Z",
"dateReserved": "2026-04-29T08:21:07.253Z",
"dateUpdated": "2026-06-10T07:47:47.578Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
Loading timeline…
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.