CVE-2026-121876

{"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": "2026-11-12T18:49:52.690Z"}, "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 \u2014 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\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"}], "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": "2026-11-12T18:49:52.690Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

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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 \u2014 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."}], "id": "CVE-2026-121876", "lastModified": "2026-11-12T17:17:29.170", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 1.5, "impactScore": 5.8, "source": "secalert@redhat.com", "type": "Primary"}]}, "published": "2026-11-12T17:17:29.040", "references": [{"source": "secalert@redhat.com", "url": "https://access.redhat.com/security/cve/CVE-2026-121876"}, {"source": "secalert@redhat.com", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2558210"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-359"}], "source": "secalert@redhat.com", "type": "Primary"}]}

{"acknowledgement": "Red Hat would like to thank Spyros Seimenis (Edgeless Systems) for reporting this issue.", "bugzilla": {"description": "sandboxed-containers: kernel: systemd-gpt-auto-generator: Guest Data Leakage in Confidential Computing (Sandboxed Containers)", "id": "2558210", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2558210"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.9", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N", "status": "draft"}, "cwe": "CWE-359", "details": ["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).\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 \u2014 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."], "mitigation": {"lang": "en:us", "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.\nThe patches released are using the following mitigation: `systemd.image_policy=root=open`.\nAlternative mitigations:\n- Disable swap specifically: add systemd.swap=0 to the kernel command line\n- Mask the generator in the guest image: \nln -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"}, "name": "CVE-2026-121876", "package_state": [{"cpe": "cpe:/a:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:rhel_els:6", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:rhel_els:7", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:rhel_els:7", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/a:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/a:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/a:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:5", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 5"}], "public_date": "2026-11-12T14:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-121876\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-121876"], "statement": "A vulnerability was found in the interaction between systemd-gpt-auto-generator and \nconfidential computing guest VM images in OpenShift Sandboxed Containers (confidential \npeer pods). systemd-gpt-auto-generator automatically discovers and mounts GPT \npartitions by type GUID at boot with no user confirmation.\nA malicious host, 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.\nNote: The CVE is published on 12th November 2026, in accordance with the researcher's proposal to release their own security advisories on that date.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Red Hat Enterprise Linux 10", "source": "cna", "vendor": "Red Hat"}, "product": "enterprise_linux", "vendor": "red_hat"}, {"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Red Hat Enterprise Linux 10", "source": "cna", "vendor": "Red Hat"}, "product": "enterprise_linux", "vendor": "redhat"}, {"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Red Hat OpenShift Container Platform 4", "source": "cna", "vendor": "Red Hat"}, "product": "openshift_container_platform", "vendor": "redhat"}], "created": "2026-11-13T04:45:14.765852+00:00", "updated": "2026-11-13T10:30:19.665921+00:00", "vendors": ["red_hat", "red_hat$PRODUCT$enterprise_linux", "redhat", "redhat$PRODUCT$enterprise_linux", "redhat$PRODUCT$openshift_container_platform"]}