CVSS 3.1
7.9 highCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:NCVE-2026-121876 Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)
High (7.9) in red hat. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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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
- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 6th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-359 Exposure of Private Personal Information to an Unauthorized Actor
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Modified
- Assigned by
- redhat (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
- red hat:red hat enterprise linux 10
- red hat:red hat enterprise linux 6
- red hat:red hat enterprise linux 7
- red hat:red hat enterprise linux 8
- red hat:red hat enterprise linux 9
- red hat:red hat openshift container platform 4
- red hat:red hat openshift container platform 5
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Ubuntu | 22.04:LTS, 24.04:LTS, 26.04:LTS and 5 more | systemd | no fix listed | UBUNTU-CVE-2026-121876 |
From the distributions' data via OSV.dev: Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Ubuntu.
Attack patterns (CAPEC)
- CAPEC-464 Evercookie Severity: Medium
- CAPEC-467 Cross Site Identification Severity: Low
- CAPEC-498 Probe iOS Screenshots
- CAPEC-508 Shoulder Surfing Likelihood: High · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.