{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-121876", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-11-04T10:34:49.034Z", "datePublished": "2026-11-12T16:55:35.424Z", "dateUpdated": "2026-11-12T16:55:35.424Z" }, "containers": { "cna": { "title": "Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)", "metrics": [ { "other": { "content": { "value": "Important", "namespace": "https://access.redhat.com/security/updates/classification/" }, "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" } ], "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." } ], "affected": [ { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:enterprise_linux:10" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel", "defaultStatus": "affected", "cpes": [ "cpe:/o:redhat:rhel_els:6" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel", "defaultStatus": "affected", "cpes": [ "cpe:/o:redhat:rhel_els:7" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel-rt", "defaultStatus": "affected", "cpes": [ "cpe:/o:redhat:rhel_els:7" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:enterprise_linux:8" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel-rt", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:enterprise_linux:8" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:enterprise_linux:9" ] }, { "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "kernel-rt", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:enterprise_linux:9" ] }, { "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-8", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:openshift:4" ] }, { "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-9", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:openshift:4" ] }, { "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 5", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "openshift/ose-rhel-coreos-9", "defaultStatus": "affected", "cpes": [ "cpe:/a:redhat:openshift:5" ] } ], "references": [ { "url": "https://access.redhat.com/security/cve/CVE-2026-121876", "tags": [ "vdb-entry", "x_refsource_REDHAT" ] }, { "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2558210", "name": "RHBZ#2558210", "tags": [ "issue-tracking", "x_refsource_REDHAT" ] } ], "datePublic": "2026-11-12T14:00:00.000Z", "problemTypes": [ { "descriptions": [ { "cweId": "CWE-359", "description": "Exposure of Private Personal Information to an Unauthorized Actor", "lang": "en", "type": "CWE" } ] } ], "x_redhatCweChain": "CWE-359: Exposure of Private Personal Information to an Unauthorized Actor", "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" } ], "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." } ], "credits": [ { "lang": "en", "value": "Red Hat would like to thank Spyros Seimenis (Edgeless Systems) for reporting this issue." } ], "providerMetadata": { "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-11-12T16:55:35.424Z" }, "x_generator": { "engine": "cvelib 1.8.0" } } } }