{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-6420", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-04-16T06:03:46.656Z", "datePublished": "2026-05-06T10:19:39.121Z", "dateUpdated": "2026-05-06T10:19:39.121Z"}, "containers": {"cna": {"title": "Keylime: keylime: security bypass due to hardcoded tpm quote nonce", "metrics": [{"other": {"content": {"value": "Moderate", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "LOW", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L", "version": "3.1"}, "format": "CVSS"}], "descriptions": [{"lang": "en", "value": "A flaw was found in Keylime. An attacker with root access on an enrolled monitored machine, where the Keylime agent runs, can exploit a vulnerability in the Keylime verifier. The verifier uses a hardcoded challenge nonce for Trusted Platform Module (TPM) quote attestation instead of a cryptographically random value. This allows the attacker to stockpile valid TPM quotes and replay them to evade detection after compromising the system. This issue affects only the push model deployment."}], "affected": [{"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "keylime", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:10"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "keylime", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:9"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-6420", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2458889", "name": "RHBZ#2458889", "tags": ["issue-tracking", "x_refsource_REDHAT"]}], "datePublic": "2026-05-06T10:00:00.000Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-1241", "description": "Use of Predictable Algorithm in Random Number Generator", "lang": "en", "type": "CWE"}]}], "x_redhatCweChain": "CWE-1241: Use of Predictable Algorithm in Random Number Generator", "workarounds": [{"lang": "en", "value": "Primary fix (one-line change in keylime/models/verifier/evidence.py):\nBefore (vulnerable):\ndef generate_challenge(self, bit_length):\n\nself.challenge = Nonce.generate(bit_length)\n self.challenge = bytes.fromhex(\"49beed365aac777dae23564f5ad0ec\")\n\nAfter (fixed):\ndef generate_challenge(self, bit_length):\nself.challenge = Nonce.generate(bit_length)\n\nExisting partial mitigations (already active):\n\n1. TPM clock monotonicity check: limits each quote to one replay.\n2. Push attestation timeout (default 10s): constrains the quote generation window, but TPM throughput allows 50-200 quotes to be stockpiled in that time."}], "timeline": [{"lang": "en", "time": "2026-04-16T06:01:38.993Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-05-06T10:00:00.000Z", "value": "Made public."}], "credits": [{"lang": "en", "value": "Red Hat would like to thank Keylime developers for reporting this issue."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-05-06T10:19:39.121Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in Keylime. An attacker with root access on an enrolled monitored machine, where the Keylime agent runs, can exploit a vulnerability in the Keylime verifier. The verifier uses a hardcoded challenge nonce for Trusted Platform Module (TPM) quote attestation instead of a cryptographically random value. This allows the attacker to stockpile valid TPM quotes and replay them to evade detection after compromising the system. This issue affects only the push model deployment."}], "id": "CVE-2026-6420", "lastModified": "2026-05-06T11:16:05.193", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "LOW", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L", "version": "3.1"}, "exploitabilityScore": 0.8, "impactScore": 5.5, "source": "secalert@redhat.com", "type": "Primary"}]}, "published": "2026-05-06T11:16:05.193", "references": [{"source": "secalert@redhat.com", "url": "https://access.redhat.com/security/cve/CVE-2026-6420"}, {"source": "secalert@redhat.com", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2458889"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1241"}], "source": "secalert@redhat.com", "type": "Primary"}]}

{"acknowledgement": "Red Hat would like to thank Keylime developers for reporting this issue.", "bugzilla": {"description": "keylime: Keylime: Security bypass due to hardcoded TPM quote nonce", "id": "2458889", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2458889"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.3", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L", "status": "draft"}, "cwe": "CWE-1241", "details": ["A flaw was found in Keylime. An attacker with root access on an enrolled monitored machine, where the Keylime agent runs, can exploit a vulnerability in the Keylime verifier. The verifier uses a hardcoded challenge nonce for Trusted Platform Module (TPM) quote attestation instead of a cryptographically random value. This allows the attacker to stockpile valid TPM quotes and replay them to evade detection after compromising the system. This issue affects only the push model deployment."], "mitigation": {"lang": "en:us", "value": "Primary fix (one-line change in keylime/models/verifier/evidence.py):\nBefore (vulnerable):\ndef generate_challenge(self, bit_length):\nself.challenge = Nonce.generate(bit_length)\nself.challenge = bytes.fromhex(\"49beed365aac777dae23564f5ad0ec\")\nAfter (fixed):\ndef generate_challenge(self, bit_length):\nself.challenge = Nonce.generate(bit_length)\nExisting partial mitigations (already active):\n1. TPM clock monotonicity check: limits each quote to one replay.\n2. Push attestation timeout (default 10s): constrains the quote generation window, but TPM throughput allows 50-200 quotes to be stockpiled in that time."}, "name": "CVE-2026-6420", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "keylime", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "keylime", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-05-06T10:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-6420\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-6420"], "threat_severity": "Moderate"}

{"created": "2026-05-06T12:00:03.490243+00:00", "updated": "2026-05-06T12:00:03.490254+00:00", "vendors": []}