x86/vmscape: Add conditional IBPB mitigation
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Configuration 2 [-]
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No data.
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | — |
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4327-1 | linux security update |
Debian DLA |
DLA-4328-1 | linux-6.1 security update |
Debian DSA |
DSA-6008-1 | linux security update |
Debian DSA |
DSA-6009-1 | linux security update |
EUVD |
EUVD-2025-28976 | In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing mitigations already protect kernel/KVM from a malicious guest. Userspace can additionally be protected by flushing the branch predictors after a VMexit. Since it is the userspace that consumes the poisoned branch predictors, conditionally issue an IBPB after a VMexit and before returning to userspace. Workloads that frequently switch between hypervisor and userspace will incur the most overhead from the new IBPB. This new IBPB is not integrated with the existing IBPB sites. For instance, a task can use the existing speculation control prctl() to get an IBPB at context switch time. With this implementation, the IBPB is doubled up: one at context switch and another before running userspace. The intent is to integrate and optimize these cases post-embargo. [ dhansen: elaborate on suboptimal IBPB solution ] |
Ubuntu USN |
USN-7850-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7853-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7853-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7854-1 | Linux kernel (KVM) vulnerabilities |
Ubuntu USN |
USN-7860-1 | Linux kernel vulnerability |
Ubuntu USN |
USN-7861-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7862-1 | Linux kernel vulnerability |
Ubuntu USN |
USN-7863-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7860-2 | Linux kernel (Real-time) vulnerability |
Ubuntu USN |
USN-7861-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7864-1 | Linux kernel (GCP and GKE) vulnerabilities |
Ubuntu USN |
USN-7860-3 | Linux kernel (FIPS) vulnerability |
Ubuntu USN |
USN-7860-4 | Linux kernel (Real-time) vulnerability |
Ubuntu USN |
USN-7853-3 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7862-2 | Linux kernel vulnerability |
Ubuntu USN |
USN-7865-1 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7861-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7862-3 | Linux kernel (Xilinx ZynqMP) vulnerability |
Ubuntu USN |
USN-7874-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7874-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7861-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-7875-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-7861-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7910-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7874-3 | Linux kernel (IoT) vulnerabilities |
Ubuntu USN |
USN-7910-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7933-1 | Linux kernel (KVM) vulnerabilities |
Ubuntu USN |
USN-7934-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7935-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7937-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7938-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7939-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7939-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7940-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7940-2 | Linux kernel (Azure, N-Series) vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.391% probability within 30 days)
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ssvc
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Debian
Debian debian Linux |
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| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* |
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| Vendors & Products |
Debian
Debian debian Linux |
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cvssV3_1
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cvssV3_1
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| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
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Linux
Linux linux Kernel |
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| Vendors & Products |
Linux
Linux linux Kernel |
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| Weaknesses | CWE-402 | |
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threat_severity
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cvssV3_1
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| Description | In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing mitigations already protect kernel/KVM from a malicious guest. Userspace can additionally be protected by flushing the branch predictors after a VMexit. Since it is the userspace that consumes the poisoned branch predictors, conditionally issue an IBPB after a VMexit and before returning to userspace. Workloads that frequently switch between hypervisor and userspace will incur the most overhead from the new IBPB. This new IBPB is not integrated with the existing IBPB sites. For instance, a task can use the existing speculation control prctl() to get an IBPB at context switch time. With this implementation, the IBPB is doubled up: one at context switch and another before running userspace. The intent is to integrate and optimize these cases post-embargo. [ dhansen: elaborate on suboptimal IBPB solution ] | |
| Title | x86/vmscape: Add conditional IBPB mitigation | |
| References |
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