CVE-2023-43634: Config Partition Not Protected by Measured Boot

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-21 · updated 2026-06-17
Weakness: CWE-522

Description

When sealing/unsealing the “vault” key, a list of PCRs is used, which defines which PCRs are used. In a previous project, CYMOTIVE found that the configuration is not protected by the secure boot, and in response Zededa implemented measurements on the config partition that was mapped to PCR 13. In that process, PCR 13 was added to the list of PCRs that seal/unseal the key. In commit “56e589749c6ff58ded862d39535d43253b249acf”, the config partition measurement moved from PCR 13 to PCR 14, but PCR 14 was not added to the list of PCRs that seal/unseal the key. This change makes the measurement of PCR 14 effectively redundant as it would not affect the sealing/unsealing of the key. An attacker could modify the config partition without triggering the measured boot, this could result in the attacker gaining full control over the device with full access to the contents of the encrypted “vault”

Affected products

LF-Edge, Zededa EVE OS: before 8.6.0; from 9.0.0 before 9.5.0 — fixed in 8.6.0, 9.5.0

How to fix

Upgrade to a fixed version: LF-Edge, Zededa EVE OS 8.6.0, 9.5.0. Check the vendor advisory for mitigations.

References

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