How severe is CVE-2026-6420?

CVE-2026-6420 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2026-6420 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-6420?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-6420 have an EU (EUVD) identifier?

Yes. CVE-2026-6420 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27657.

When was CVE-2026-6420 published?

CVE-2026-6420 was published on 2026-05-06 and last updated on 2026-06-24.

CVE-2026-6420

CVE-2026-6420 is a medium-severity vulnerability with a CVSS 3.x base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1241.

Key facts

Severity: Medium (CVSS 3.x base score 6.3)
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27657
Weakness: CWE-1241
Published: 2026-05-06
Last modified: 2026-06-24

Description

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.

Frequently asked questions

What is CVE-2026-6420?: 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.
How severe is CVE-2026-6420?: CVE-2026-6420 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2026-6420 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-6420?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-6420 have an EU (EUVD) identifier?: Yes. CVE-2026-6420 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27657.
When was CVE-2026-6420 published?: CVE-2026-6420 was published on 2026-05-06 and last updated on 2026-06-24.

References

Other CWE-1241 vulnerabilities

CVE-2023-4695 — High (CVSS 8.1): Use of Predictable Algorithm in Random Number Generator in GitHub repository pkp/pkp-lib prior to 3.3.0-16.
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