CVE-2026-54872
Full vulnerability record from the local CVENow database.
Description
Issue summary: The generic elliptic-curve scalar multiplication used for ECDSA and SM2 signature operations with curves that do not have a dedicated implementation leaks information about the secret nonce through timing. Impact summary: An attacker able to measure signing times may learn information about the per-signature secret nonce, which over many signatures can, via a lattice / Hidden Number Problem attack, lead to recovery of the private key. CWE: CWE-208: Observable Timing Discrepancy Description: The generic elliptic-curve scalar multiplication used for curves that do not have a dedicated constant-time implementation pads the secret scalar with non-constant-time BIGNUM operations, so the time taken depends on the value of the secret scalar derived from the ECDSA and SM2 nonce. The leak is very small; observing it requires a large number of measurements. The effect is largest for curves whose group order lies on a machine-word boundary, such as brainpoolP384r1. Applications using ECDSA signing over the Brainpool and other generic prime curves, and SM2 signing on platforms that use the generic implementation, are vulnerable to this issue. The NIST curves P-256, P-384 and P-521 use dedicated constant-time implementations and are not affected. FIPS Impact: no The FIPS modules are not affected: the approved NIST curves used in the FIPS provider have dedicated constant-time implementations and do not use the affected code path.
Severity
LOW
CVSS score
3.7
(v3.1)
Vulnerability status
Modified
Source identifier
Published
2026-09-29 16:17:08.623000
Last modified
2026-11-10 13:19:26.240000
View original CVE JSON
{
"id": "CVE-2026-54872",
"sourceIdentifier": "[email protected]",
"published": "2026-09-29T16:17:08.623",
"lastModified": "2026-11-10T13:19:26.240",
"vulnStatus": "Modified",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Issue summary: The generic elliptic-curve scalar multiplication used for\nECDSA and SM2 signature operations with curves that do not have a dedicated\nimplementation leaks information about the secret nonce through timing.\n\nImpact summary: An attacker able to measure signing times may learn\ninformation about the per-signature secret nonce, which over many signatures\ncan, via a lattice / Hidden Number Problem attack, lead to recovery of the\nprivate key.\n\nCWE: CWE-208: Observable Timing Discrepancy\n\nDescription: The generic elliptic-curve scalar multiplication used for\ncurves that do not have a dedicated constant-time implementation pads the\nsecret scalar with non-constant-time BIGNUM operations, so the time taken\ndepends on the value of the secret scalar derived from the ECDSA and SM2 nonce.\n\nThe leak is very small; observing it requires a large number of\nmeasurements. The effect is largest for curves whose group order lies\non a machine-word boundary, such as brainpoolP384r1.\n\nApplications using ECDSA signing over the Brainpool and other generic prime\ncurves, and SM2 signing on platforms that use the generic implementation,\nare vulnerable to this issue.\n\nThe NIST curves P-256, P-384 and P-521 use dedicated constant-time\nimplementations and are not affected.\n\nFIPS Impact: no\nThe FIPS modules are not affected: the approved NIST curves used in the FIPS\nprovider have dedicated constant-time implementations and do not use the\naffected code path."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "OpenSSL",
"product": "OpenSSL",
"defaultStatus": "unaffected",
"versions": [
{
"version": "4.0.0",
"lessThan": "4.0.3",
"versionType": "semver",
"status": "affected"
},
{
"version": "3.6.0",
"lessThan": "3.6.5",
"versionType": "semver",
"status": "affected"
},
{
"version": "3.5.0",
"lessThan": "3.5.9",
"versionType": "semver",
"status": "affected"
},
{
"version": "3.4.0",
"lessThan": "3.4.8",
"versionType": "semver",
"status": "affected"
},
{
"version": "3.0.0",
"lessThan": "3.0.23",
"versionType": "semver",
"status": "affected"
},
{
"version": "1.1.1",
"lessThan": "1.1.1zj",
"versionType": "custom",
"status": "affected"
},
{
"version": "1.0.2",
"lessThan": "1.0.2zs",
"versionType": "custom",
"status": "affected"
}
]
}
]
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"affectedData": [
{
"vendor": "Siemens",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)",
"defaultStatus": "unknown",
"versions": [
{
"version": "V3.1.7",
"lessThan": "*",
"versionType": "custom",
"status": "affected"
}
]
},
{
"vendor": "Siemens",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)",
"defaultStatus": "unknown",
"versions": [
{
"version": "V3.1.7",
"lessThan": "*",
"versionType": "custom",
"status": "affected"
}
]
},
{
"vendor": "Siemens",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)",
"defaultStatus": "unknown",
"versions": [
{
"version": "V3.1.7",
"lessThan": "*",
"versionType": "custom",
"status": "affected"
}
]
},
{
"vendor": "Siemens",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)",
"defaultStatus": "unknown",
"versions": [
{
"version": "V3.1.7",
"lessThan": "*",
"versionType": "custom",
"status": "affected"
}
]
},
{
"vendor": "Siemens",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)",
"defaultStatus": "unknown",
"versions": [
{
"version": "V3.1.7",
"lessThan": "*",
"versionType": "custom",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"baseScore": 3.7,
"baseSeverity": "LOW",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 2.2,
"impactScore": 1.4
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-09-29T17:27:46.959054Z",
"id": "CVE-2026-54872",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-208"
}
]
}
],
"configurations": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "1.0.2",
"versionEndExcluding": "1.0.2zs",
"matchCriteriaId": "B6D38C82-B694-4F0F-B042-AC83B014968B"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "1.1.1",
"versionEndExcluding": "1.1.1zj",
"matchCriteriaId": "AB24C69B-F66B-4BC6-99E8-4D3088607B00"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.0.0",
"versionEndExcluding": "3.0.23",
"matchCriteriaId": "C9AFA409-BE77-40FB-8191-3405AC8F52C0"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.4.0",
"versionEndExcluding": "3.4.8",
"matchCriteriaId": "707E1EC7-0538-4F9F-96CB-C89FECC1F3ED"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.5.0",
"versionEndExcluding": "3.5.9",
"matchCriteriaId": "B822E02B-8728-4C34-98BC-52D0A0A735B3"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.6.0",
"versionEndExcluding": "3.6.5",
"matchCriteriaId": "96C892B6-618B-4CB9-85B6-76C641D17532"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.0.0",
"versionEndExcluding": "4.0.3",
"matchCriteriaId": "BC4A99CC-483D-4C81-A95F-6AEB2BF1B500"
}
]
}
]
}
],
"references": [
{
"url": "https://github.com/openssl/openssl/commit/1a5bee8dc57430a2be69cd1ffe7fec6a62f4f179",
"source": "[email protected]",
"tags": [
"Patch"
]
},
{
"url": "https://github.com/openssl/openssl/commit/3f7e1363dccec6f7732bb9e9fa471bb6e4aa68cb",
"source": "[email protected]",
"tags": [
"Patch"
]
},
{
"url": "https://github.com/openssl/openssl/commit/7d83bc7764999dfd91b83b4f0815b45390422afd",
"source": "[email protected]",
"tags": [
"Patch"
]
},
{
"url": "https://github.com/openssl/openssl/commit/8166827a78aad164a07aa86dea2b425403ced471",
"source": "[email protected]",
"tags": [
"Patch"
]
},
{
"url": "https://openssl-library.org/news/secadv/20260929.txt",
"source": "[email protected]",
"tags": [
"Vendor Advisory"
]
},
{
"url": "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
}
]
}