{"api_version":"1","generated_at":"2026-11-12T21:55:18+00:00","cve":"CVE-2026-121876","urls":{"html":"https://cve.report/CVE-2026-121876","api":"https://cve.report/api/cve/CVE-2026-121876.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-121876","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-121876"},"summary":{"title":"Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)","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.","state":"PUBLISHED","assigner":"redhat","published_at":"2026-11-12 17:17:29","updated_at":"2026-11-12 17:17:29"},"problem_types":["CWE-359","CWE-359 Exposure of Private Personal Information to an Unauthorized Actor"],"metrics":[{"version":"3.1","source":"secalert@redhat.com","type":"Primary","score":"7.9","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","baseScore":7.9,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"7.9","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","data":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":7.9,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"HIGH","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2558210","name":"https://bugzilla.redhat.com/show_bug.cgi?id=2558210","refsource":"secalert@redhat.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://access.redhat.com/security/cve/CVE-2026-121876","name":"https://access.redhat.com/security/cve/CVE-2026-121876","refsource":"secalert@redhat.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-121876","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121876","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","version":"","platforms":[]},{"source":"CNA","vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 5","version":"","platforms":[]}],"timeline":[{"source":"CNA","time":"2026-10-16T00:00:00.000Z","lang":"en","value":"Reported to Red Hat."},{"source":"CNA","time":"2026-11-12T14:00:00.000Z","lang":"en","value":"Made public."}],"solutions":[],"workarounds":[{"source":"CNA","title":"","value":"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\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","time":"","lang":"en"}],"exploits":[],"credits":[{"source":"CNA","value":"Red Hat would like to thank Spyros Seimenis (Edgeless Systems) for reporting this issue.","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:enterprise_linux:10"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 10","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:rhel_els:6"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 6","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:rhel_els:7"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:rhel_els:7"],"defaultStatus":"affected","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 7","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:enterprise_linux:8"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:enterprise_linux:8"],"defaultStatus":"affected","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:enterprise_linux:9"],"defaultStatus":"affected","packageName":"kernel","product":"Red Hat Enterprise Linux 9","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:enterprise_linux:9"],"defaultStatus":"affected","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 9","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"],"defaultStatus":"affected","packageName":"openshift/ose-rhel-coreos-8","product":"Red Hat OpenShift Container Platform 4","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:4"],"defaultStatus":"affected","packageName":"openshift/ose-rhel-coreos-9","product":"Red Hat OpenShift Container Platform 4","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/a:redhat:openshift:5"],"defaultStatus":"affected","packageName":"openshift/ose-rhel-coreos-9","product":"Red Hat OpenShift Container Platform 5","vendor":"Red Hat"}],"credits":[{"lang":"en","value":"Red Hat would like to thank Spyros Seimenis (Edgeless Systems) for reporting this issue."}],"datePublic":"2026-11-12T14:00:00.000Z","descriptions":[{"lang":"en","value":"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."}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Important"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":7.9,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"HIGH","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-359","description":"Exposure of Private Personal Information to an Unauthorized Actor","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-12T16:55:35.424Z","orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","shortName":"redhat"},"references":[{"tags":["vdb-entry","x_refsource_REDHAT"],"url":"https://access.redhat.com/security/cve/CVE-2026-121876"},{"name":"RHBZ#2558210","tags":["issue-tracking","x_refsource_REDHAT"],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2558210"}],"timeline":[{"lang":"en","time":"2026-10-16T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-11-12T14:00:00.000Z","value":"Made public."}],"title":"Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)","workarounds":[{"lang":"en","value":"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\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"}],"x_generator":{"engine":"cvelib 1.8.0"},"x_redhatCweChain":"CWE-359: Exposure of Private Personal Information to an Unauthorized Actor"}},"cveMetadata":{"assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","assignerShortName":"redhat","cveId":"CVE-2026-121876","datePublished":"2026-11-12T16:55:35.424Z","dateReserved":"2026-11-04T10:34:49.034Z","dateUpdated":"2026-11-12T16:55:35.424Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-12 17:17:29","lastModifiedDate":"2026-11-12 17:17:29","problem_types":["CWE-359","CWE-359 Exposure of Private Personal Information to an Unauthorized Actor"],"metrics":{"cvssMetricV31":[{"source":"secalert@redhat.com","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","baseScore":7.9,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":1.5,"impactScore":5.8}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"121876","Ordinal":"1","Title":"Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest ","CVE":"CVE-2026-121876","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"121876","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest "}]}}}