{"affected":[{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel","product":"Red Hat Enterprise Linux 10","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel","product":"Red Hat Enterprise Linux 6","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel","product":"Red Hat Enterprise Linux 7","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 7","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel","product":"Red Hat Enterprise Linux 8","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 8","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel","product":"Red Hat Enterprise Linux 9","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 9","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-8","product":"Red Hat OpenShift Container Platform 4","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-9","product":"Red Hat OpenShift Container Platform 4","source":"CNA: redhat","vendor":"Red Hat","versions":[]},{"defaultStatus":"affected","ecosystem":"https://access.redhat.com/downloads/content/package-browser/","packageName":"openshift/ose-rhel-coreos-9","product":"Red Hat OpenShift Container Platform 5","source":"CNA: redhat","vendor":"Red Hat","versions":[]}],"cveId":"CVE-2026-121876","cwes":["CWE-359"],"description":"A flaw was found in the interaction between systemd-gpt-auto-generator and \nconfidential computing guest VM images in OpenShift Sandboxed Containers \n(confidential peer pods). systemd-gpt-auto-generator automatically discovers \nand mounts GPT partitions by type GUID at boot with no user confirmation. In \nthe confidential computing threat model, where the host/hypervisor is the \nadversary, a malicious host can inject partitions into the guest's virtual \ndisk. Most critically, injecting a swap partition causes the guest kernel to \npage out TEE-encrypted memory to a host-controlled block device, breaking the \nconfidentiality guarantee of the hardware TEE (AMD SEV-SNP, Intel TDX).\n\nThe PodVM images use a GPT-partitioned disk with dm-verity on the root \npartition. However, the roothash= kernel parameter only disables root \nauto-discovery — non-root partitions (swap, /home, /var, /srv, /var/tmp) are \nstill auto-discovered and mounted. The generator is shipped unmasked in the \nRHEL systemd-udev subpackage, and no kernel command line parameter in the \nmeasured UKI addon disables it. Additionally, the PodVM measurement script \ncaptures PCRs 3, 9, 11, and 12, but not PCR 5 (GPT partition table), so \npartition table modifications are not detected by remote attestation.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":7.9,"severity":"high","source":"CNA: redhat","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","version":"3.1"},{"score":7.9,"severity":"high","source":"NVD: secalert@redhat.com","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}],"modifiedAt":1794509392690,"publishedAt":1794502535424,"references":[{"source":"CNA: redhat","tags":["vdb-entry","x_refsource_REDHAT"],"url":"https://access.redhat.com/security/cve/CVE-2026-121876"},{"source":"CNA: redhat","tags":["issue-tracking","x_refsource_REDHAT"],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2558210"},{"source":"secalert@redhat.com","tags":[],"url":"https://access.redhat.com/security/cve/CVE-2026-121876"},{"source":"secalert@redhat.com","tags":[],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2558210"}],"remediation":[{"kind":"workaround","source":"CNA: redhat","text":"Add systemd.gpt_auto=0 to the measured kernel command line (UKI addon) to completely \ndisable systemd-gpt-auto-generator. Since the PodVM already uses explicit partition \nlayout and dm-verity, auto-discovery is unnecessary.\n\nThe patches released are using the following mitigation: `systemd.image_policy=root=open`.\n\nAlternative mitigations:\n- Disable swap specifically: add systemd.swap=0 to the kernel command line\n- Mask the generator in the guest image: \n  ln -sf /dev/null /etc/systemd/system-generators/systemd-gpt-auto-generator\n- Include PCR 5 in the PodVM measurement script alongside PCRs 3, 9, 11, 12\n- For systemd 254+: set restrictive image policy via systemd.image_policy=root=verity+signed+encrypted+unprotected+absent:swap=absent:home=absent:srv=absent:var=absent:tmp=absent"}],"revision":"ee8bf1f329573e6a58a104a84a6e9f11ade256cc7f1f22308f439581d83c4571","sources":[{"modifiedAt":1794509392690,"name":"CNA: redhat","retrievedAt":1794510538376,"url":"https://www.cve.org/CVERecord?id=CVE-2026-121876"},{"modifiedAt":1794503849170,"name":"NVD","retrievedAt":1794507522611,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121876"}],"ssvc":null,"status":"published","title":"Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)","updatedAt":1794510538376}