{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "OpenSSL",
"vendor": "OpenSSL",
"versions": [
{
"lessThan": "4.0.2",
"status": "affected",
"version": "4.0.0",
"versionType": "semver"
},
{
"lessThan": "3.6.4",
"status": "affected",
"version": "3.6.0",
"versionType": "semver"
},
{
"lessThan": "3.5.8",
"status": "affected",
"version": "3.5.0",
"versionType": "semver"
},
{
"lessThan": "3.4.7",
"status": "affected",
"version": "3.4.0",
"versionType": "semver"
},
{
"lessThan": "3.0.22",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
},
{
"lessThan": "1.1.1zi",
"status": "affected",
"version": "1.1.1",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "Bhabani Sankar Das"
},
{
"lang": "en",
"type": "reporter",
"value": "Filipe Casal(Trail of Bits)"
},
{
"lang": "en",
"type": "remediation developer",
"value": "Daniel Kubec"
}
],
"datePublic": "2026-08-25T13:36:16+02:00",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based
on querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive
can write and cleanse more bytes than that query reports, causing an 8-byte
out-of-bounds heap write.
Impact summary: An attacker who supplies a crafted CMS message can trigger a
deterministic 8-byte out-of-bounds heap write when the victim decrypts it
with CMS_decrypt(), corrupting the heap and typically resulting in a Denial
of Service.
CWE: CWE-787: Out-of-bounds Write
Description: The key-wrap OID is potentially attacker-controlled on the wire.
CMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers.
An attacker can take a legitimate message and change a single OID byte to
select the padded variant while leaving the message otherwise valid. Since
the unwrap key is derived from the recipient's private operation (ECDH key
agreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot
pass, and the decryption fails with integrity failure.
The write is a fixed-size (8-byte), fixed-value (zero) heap overflow
immediately past the allocation, requires no special configuration, and is
reachable from the public CMS_decrypt() function. The consequence is
a heap corruption leading to a Denial of Service. The fix in the CMS code
sizes the unwrap output buffer for the worst case so a failed unwrap cannot
write past the allocation.
FIPS impact: no
As the CMS code lives outside the FIPS module boundary, no FIPS
modules are affected by this CVE."
}
],
"value": "Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based\non querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive\ncan write and cleanse more bytes than that query reports, causing an 8-byte\nout-of-bounds heap write.\n\nImpact summary: An attacker who supplies a crafted CMS message can trigger a\ndeterministic 8-byte out-of-bounds heap write when the victim decrypts it\nwith CMS_decrypt(), corrupting the heap and typically resulting in a Denial\nof Service.\n\nCWE: CWE-787: Out-of-bounds Write\n\nDescription: The key-wrap OID is potentially attacker-controlled on the wire.\nCMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers.\nAn attacker can take a legitimate message and change a single OID byte to\nselect the padded variant while leaving the message otherwise valid. Since\nthe unwrap key is derived from the recipient's private operation (ECDH key\nagreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot\npass, and the decryption fails with integrity failure.\n\nThe write is a fixed-size (8-byte), fixed-value (zero) heap overflow\nimmediately past the allocation, requires no special configuration, and is\nreachable from the public CMS_decrypt() function. The consequence is\na heap corruption leading to a Denial of Service. The fix in the CMS code\nsizes the unwrap output buffer for the worst case so a failed unwrap cannot\nwrite past the allocation.\n\nFIPS impact: no\n\nAs the CMS code lives outside the FIPS module boundary, no FIPS\nmodules are affected by this CVE."
}
],
"metrics": [
{
"format": "other",
"other": {
"content": {
"text": "Moderate"
},
"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": {
"orgId": "00000000-0000-4000-9000-000000000000",
"shortName": "openssl"
},
"references": [
{
"name": "OpenSSL Advisory",
"tags": [
"vendor-advisory"
],
"url": "https://openssl-library.org/news/secadv/20260825.txt"
},
{
"name": "4.0.2 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/9530a5fd1aacaeccdced4478ea2340a480613335"
},
{
"name": "3.6.4 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/2a3dac874c8057c1f0186849bf1ede1ae7b6b756"
},
{
"name": "3.5.8 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/87784ad619af36b8807c2044b3940006fccc1e42"
},
{
"name": "3.4.7 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/9ec2f6d2ae2bcad907cf7ee38584855bafe4979a"
},
{
"name": "3.0.22 git commit",
"tags": [
"patch"
],
"url": "https://github.com/openssl/openssl/commit/a0c8ec557d9cac078f032d76cdf684fe743eb382"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "Heap Buffer Overflow in CMS Key Unwrapping",
"x_generator": {
"engine": "Vulnogram 0.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "00000000-0000-4000-9000-000000000000",
"cveId": "CVE-2026-63072",
"requesterUserId": "00000000-0000-4000-9000-000000000000",
"serial": 1,
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}