{"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"}}}}