systemd-gpt-auto-generator auto-mount enables TEE memory leak in OpenShift
CVE-2026-121876 Published on November 12, 2026
Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)
A flaw was found in the interaction between systemd-gpt-auto-generator and
confidential computing guest VM images in OpenShift Sandboxed Containers
(confidential peer pods). systemd-gpt-auto-generator automatically discovers
and mounts GPT partitions by type GUID at boot with no user confirmation. In
the confidential computing threat model, where the host/hypervisor is the
adversary, a malicious host can inject partitions into the guest's virtual
disk. Most critically, injecting a swap partition causes the guest kernel to
page out TEE-encrypted memory to a host-controlled block device, breaking the
confidentiality guarantee of the hardware TEE (AMD SEV-SNP, Intel TDX).
The PodVM images use a GPT-partitioned disk with dm-verity on the root
partition. However, the roothash= kernel parameter only disables root
auto-discovery non-root partitions (swap, /home, /var, /srv, /var/tmp) are
still auto-discovered and mounted. The generator is shipped unmasked in the
RHEL systemd-udev subpackage, and no kernel command line parameter in the
measured UKI addon disables it. Additionally, the PodVM measurement script
captures PCRs 3, 9, 11, and 12, but not PCR 5 (GPT partition table), so
partition table modifications are not detected by remote attestation.
Vulnerability Analysis
CVE-2026-121876 is exploitable with local system access, and requires user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Timeline
Reported to Red Hat.
Made public. 27 days later.
Weakness Type
What is a Privacy violation Vulnerability?
The product does not properly prevent a person's private, personal information from being accessed by actors who either (1) are not explicitly authorized to access the information or (2) do not have the implicit consent of the person about whom the information is collected.
CVE-2026-121876 has been classified to as a Privacy violation vulnerability or weakness.
Products Associated with CVE-2026-121876
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Affected Versions
Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 5:Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.