CVE-2026-123613
Full vulnerability record from the local CVENow database.
Description
Rustls from 0.23.13 before 0.23.45 accepts TLS 1.3 handshake messages at the wrong encryption level when they follow a key-changing message in the same record, because Deframer::aligned does not enforce RFC 8446 record-boundary alignment. A peer or on-path attacker can pack a plaintext EncryptedExtensions with the ServerHello, which rustls accepts unencrypted.
Severity
MEDIUM
CVSS score
6.9
(v4.0)
Vulnerability status
Received
Source identifier
Published
2026-11-08 02:16:56.780000
Last modified
2026-11-08 02:16:56.780000
View original CVE JSON
{
"id": "CVE-2026-123613",
"sourceIdentifier": "[email protected]",
"published": "2026-11-08T02:16:56.780",
"lastModified": "2026-11-08T02:16:56.780",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Rustls from 0.23.13 before 0.23.45 accepts TLS 1.3 handshake messages at the wrong encryption level when they follow a key-changing message in the same record, because Deframer::aligned does not enforce RFC 8446 record-boundary alignment. A peer or on-path attacker can pack a plaintext EncryptedExtensions with the ServerHello, which rustls accepts unencrypted."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "rustls",
"product": "rustls",
"defaultStatus": "unaffected",
"packageURL": "pkg:cargo/rustls",
"versions": [
{
"version": "0.23.13",
"lessThan": "0.23.45",
"versionType": "semver",
"status": "affected"
},
{
"version": "0.23.45",
"versionType": "semver",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV40": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "4.0",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/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",
"baseScore": 6.9,
"baseSeverity": "MEDIUM",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"vulnConfidentialityImpact": "LOW",
"vulnIntegrityImpact": "NONE",
"vulnAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"subAvailabilityImpact": "NONE",
"exploitMaturity": "NOT_DEFINED",
"confidentialityRequirement": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"availabilityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"valueDensity": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED"
}
}
],
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Primary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 3.9,
"impactScore": 1.4
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Primary",
"description": [
{
"lang": "en",
"value": "CWE-20"
}
]
}
],
"references": [
{
"url": "https://github.com/rustls/rustls/commit/5046bdf8a612b35a2c1a9e168054c1d5c65e7dd7",
"source": "[email protected]"
},
{
"url": "https://github.com/rustls/rustls/security/advisories/GHSA-2mjx-qc3c-rqvc",
"source": "[email protected]"
},
{
"url": "https://www.vulncheck.com/advisories/rustls-0.23.13-before-0.23.45-tls-1.3-handshake-encryption-level-bypass",
"source": "[email protected]"
}
]
}