CVE-2026-121876 (GCVE-0-2026-121876)

Vulnerability from cvelistv5 – Published: 2026-11-12 16:55 – Updated: 2026-11-12 18:49
VLAI
Title
Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)
Summary
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.
Severity
7.9 (High)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
CWE
  • CWE-359 - Exposure of Private Personal Information to an Unauthorized Actor
Assigner
redhat CNA under the redhat root
CNA scorecard B 82/100 over 1204 records in the last 180 days details
References
URL Tags
https://access.redhat.com/security/cve/CVE-2026-121876 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2558210 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-11-12 14:00
Credits
Red Hat would like to thank Spyros Seimenis (Edgeless Systems) for reporting this issue.
Show details on NVD website
To clipboard 

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