Keylime security bypass via hardcoded TPM attestation nonce

Severity: medium · CVSS 6.3 · Published 2026-05-06

Keylime is a security tool used to verify the integrity of remote computers using hardware-based security chips (TPMs). A vulnerability in the 'push model' deployment allows an attacker who already has administrative access to a monitored machine to bypass security checks. By replaying old, valid security 'quotes,' the attacker can hide the fact that they have compromised the system, potentially maintaining undetected access.

Technologies: keylime (PyPI). Vendors: PyPI.

Quick answers

Is This vulnerability exploited in the wild?
No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?
Medium severity, with a CVSS score of 6.3, published 6 May 2026.
Which products and versions are affected?
keylime (PyPI) >= 7.14.0, <= 7.14.1.
Is there a fix for This vulnerability?
A patch was published on 2026-06-23: Red Hat released security updates (RHSA-2026:28582) Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?
It is attacked with local access, in a software library.
Am I affected?
Check whether you run keylime (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A flaw exists in the Keylime verifier where it uses a hardcoded challenge nonce for Trusted Platform Module (TPM) quote attestation instead of a cryptographically random value. This issue specifically affects the 'push model' deployment. An attacker with root privileges on an enrolled monitored machine can exploit this by stockpiling valid TPM quotes (using tpm2_quote with the known nonce) while the system is in a clean state. After compromising the system, the attacker can replay these stockpiled quotes to the verifier to maintain a false appearance of integrity and evade detection. The vulnerability is mitigated by clock monotonicity checks, which prevent a single quote from being reused, but multiple unique quotes can be pre-generated. The issue is addressed in Keylime version 7.14.2 and various Red Hat package updates.

Affected products

  • Keylime keylime >= 7.14.0, <= 7.14.1
  • Red Hat Red Hat Enterprise Linux 10 keylime < 7.14.1-5.el10_2.1

Timeline

  • 2026-04-16: disclosed: Initial report in Red Hat Bugzilla
  • 2026-05-06: advisory: NVD and GitHub advisories published
  • 2026-05-11: other: GitHub advisory GHSA-wc6p-4gwj-jcr8 withdrawn as duplicate of GHSA-q8w6-w55c-ccv5
  • 2026-06-23: patched: Red Hat released security updates (RHSA-2026:28582)

References

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