CVE-2026-121876
Sandboxed-containers: kernel: systemd-gpt-auto-generator: guest data leakage in confidential computing (sandboxed containers)
No exploitation reported by the sources we read.
- Published2026-11-12
- WeaknessCWE-359
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
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.
Timeline
dates in UTC- 2026-11-1216:55CVE publishedCNA
Versions per branch
Products declared by the CNA
As redhat, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.
- Red Hat Enterprise Linux 10other versions: affected
package kernelhttps://access.redhat.com/downloads/content/package-browser/
- Red Hat Enterprise Linux 6other versions: affected
package kernelhttps://access.redhat.com/downloads/content/package-browser/
- Red Hat Enterprise Linux 7other versions: affected
package kernelhttps://access.redhat.com/downloads/content/package-browser/
- Red Hat Enterprise Linux 7other versions: affected
package kernel-rthttps://access.redhat.com/downloads/content/package-browser/
- Red Hat Enterprise Linux 8other versions: affected
package kernelhttps://access.redhat.com/downloads/content/package-browser/
- Red Hat Enterprise Linux 8other versions: affected
package kernel-rthttps://access.redhat.com/downloads/content/package-browser/
5 more products in the CVE record.
Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-12
Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-121876 yet.
Fix
No fix published by the sources we read yet. NVD record
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Metasploit modules
- none listed Metasploit Framework
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
- Published
- 2026-11-12
Frequently asked questions
What is CVE-2026-121876?
Is CVE-2026-121876 actively exploited?
What is the CVSS score for CVE-2026-121876?
Hear about the next vulnerability in your software
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
No credit card required · No monthly cap on website lookups · 250 API requests/month
Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.