CVE-2026-6420

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 95% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
6.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.3
EG Score
6.3(medium)
EPSS
2.2%
KEV
Not listed

Published

May 6, 2026

Last Modified

June 24, 2026

Advisory Details (2)

Auto-updated May 6, 2026
Patch available. Sources: redhat.
redhat

2458889 – (CVE-2026-6420) CVE-2026-6420 keylime: Keylime: Security bypass due to hardcoded TPM quote nonce

https://bugzilla.redhat.com/show_bug.cgi?id=2458889
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-6420

Vendor Advisories for CVE-2026-6420(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
keylime7.14.0, 7.14.17.14.2—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 34× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-13 22:31 UTCEPSS rescore
  3. 2026-07-11 08:27 UTCEPSS rescore
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  15. 2026-06-29 14:06 UTCEPSS rescore
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  17. 2026-06-28 04:56 UTCEPSS rescore
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  1. 2026-06-21 14:56 UTCEPSS rescore
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  4. 2026-06-19 19:26 UTCEPSS rescore
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  12. 2026-06-14 23:18 UTCEPSS rescore
  13. 2026-06-14 07:43 UTCEG score recompute
  14. 2026-06-13 23:00 UTCEPSS rescore
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  17. 2026-06-12 07:30 UTCEG score recompute
  18. 2026-06-11 14:00 UTCEPSS rescore
  19. 2026-06-11 07:43 UTCEG score recompute
  20. 2026-06-10 22:19 UTCEPSS rescore
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  22. 2026-06-10 07:59 UTCEG score recompute
  23. 2026-06-09 07:51 UTCEG score recompute
  24. 2026-06-08 14:17 UTCEPSS rescore
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  26. 2026-06-07 15:25 UTCEPSS rescore
  27. 2026-06-07 08:08 UTCEG score recompute
  28. 2026-06-06 13:47 UTCEPSS rescore
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  31. 2026-06-05 08:40 UTCEG score recompute
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  34. 2026-06-04 08:56 UTCEG score recompute
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  45. 2026-05-29 13:44 UTCEPSS rescore
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  51. 2026-05-26 13:44 UTCEPSS rescore
  52. 2026-05-26 07:18 UTCEPSS rescore
  53. 2026-05-23 00:08 UTCEG score recompute
  54. 2026-05-21 22:43 UTCEPSS rescore
  55. 2026-05-20 22:38 UTCEPSS rescore
  56. 2026-05-20 14:19 UTCEG score recompute
  57. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-6420?
CVE-2026-6420 is a medium vulnerability published on May 6, 2026. 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…
When was CVE-2026-6420 disclosed?
CVE-2026-6420 was first published in the National Vulnerability Database on May 6, 2026, with the most recent update on June 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6420 actively exploited?
CVE-2026-6420 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6420?
CVE-2026-6420 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-6420?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6420, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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